JPS62161642A - Recorder - Google Patents

Abstract

PURPOSE:To prevent drop of throughput in continuous printing by furnishing a transport control means to enlarge the refeeding spacing of sheets transported on the two-side or multiple purpose transport path according to the transport condition or the condition of external means. CONSTITUTION:In the case of two-side printing, an image is formed on one side of a printing sheet fed from an intermediate tray 11a, and the sheet is turned over and set in a position A on the two-side transport path 14b, and now the value obtained by adding the time T1 of the sheet feed implement routine to the time T0 is set on a timer TA, and this action is repeated in the same manner as in one-side printing. Thus the sheet feed timing from said tray 11a is delayed compared with at the time of maximum throughput, and the sheet feed timing after the position A is controlled to the time T0. Until it becomes possible to print on the second side, therefore, the spacing of sheets fed from intermediate cassette is prolonged to the time T1, to return to the sheet spacing at maximum throughput thereafter till completion of printing, and thus drop of throughput is prevented by setting the time T1 to the time from commencement of refeeding of the tray 11a to handing-over of the sheet to a roller 15.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention forms images on both sides of the paper sheet or multiple images on one side by selectively reversing the paper sheet being conveyed or while not reversing it. This relates to a recording device.

[Conventional technology]

Conventionally, the feedback conveyance path used when performing double-sided printing was used to return the printed paper to a printable state after single-sided printing, and to turn the printed paper over (reversing), or to transfer the printed paper once printed. (This process and printing on the same surface several times is called multiple printing, hereinafter abbreviated as multiple printing). This work of turning over the printed paper was performed by once stacking it on a tray called an intermediate tray and refeeding the paper. However, stacking and refeeding cannot be performed at the same time. Here, if the printer main body performs continuous double-sided printing at the maximum throughput (the number of sheets that can be printed in one minute), the sheets that have undergone single-sided printing will be sequentially conveyed to the intermediate tray at that speed. On the other hand, the intermediate tray cannot stack the print paper and refeed the print paper at the same time, so if you do not prioritize the work of stacking the print paper conveyed from the upper conveyance path, it may cause a jam. As a result, the printer had to give priority to the stacking process, re-feed the paper whenever they could, and then carry the print paper to the position where it should be delivered to the printer body and set it up.

Furthermore, once the paper refeeding operation starts, it cannot be stopped midway, so the paper refeeding operation must be completed within the time from the end of stacking to the start of stacking the next print paper. The work during multiple printing is almost the same. In other words, in reality, paper must be re-feeded within the total time of the paper width force of the print paper plus the paper interval from the end of the stack.

[Problem that the invention seeks to solve]

However, if the paper width force of the print paper of the paper size allowed by the printer body is defined as to, the paper interval of the print paper is 1. and the stacking time ts of the intermediate tray is
When the relationship in equation (1) below holds, ts > (t l+ tz ) −−
(1) The intermediate tray can only be used for stacking work and will eventually overflow, resulting in the problem that double-sided printing becomes permanently impossible and the maximum throughput (determined by the stacking time ts of the intermediate tray) also decreases.

Furthermore, if the following equation (2) holds true, t5 < (t
+ +t2) ・・・・・・(2) If the paper is not re-fed at the same interval as the print paper coming from the printer main body, the number of sheets ejected to the intermediate tray will exceed the number of sheets fed from the intermediate tray. As a result, the distance between print sheets fed from the feedback conveyance path becomes longer. For this reason, there is a problem in that in terms of the system, the position of a recording device located at a lower level is switched with respect to an external device located at a higher level.

Furthermore, apart from the fact that the interval between printed sheets output by refeeding becomes longer than the interval between sheets ejected to the intermediate tray due to the establishment of equation (2) above, continuous double-sided As printing continues, the number of sheets delivered to the intermediate tray greatly exceeds the number of sheets fed from the intermediate tray, and eventually the paper in the intermediate tray overflows, causing a jam. was there.

In addition, the intermediate tray has physical limitations that prevent it from stacking and feeding print paper at the same time, so it cannot perform random paper feeding from either the feedback conveyance path or the paper feed source. There were many problems such as a significant drop in throughput.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a recording apparatus that can prevent a decrease in throughput during continuous printing.

[Failure to solve the problem]

The recording apparatus according to the present invention is provided with a conveyance control means for extending the refeeding interval of paper sheets conveyed on a double-sided or multiple conveyance path according to the conveyance state of the paper sheets or the state of external means. It is.

[Effect]

In this invention, the conveyance control means extends the refeeding interval of the paper sheets conveyed on the double-sided or multiple conveyance path in accordance with the conveyance state of the paper sheets or the state of the external means.

〔Example〕

FIG. 1 is a sectional view illustrating the outline of a recording apparatus showing an embodiment of the present invention, in which 1 is a printer main body, and a control unit 1a.
Each part is comprehensively controlled in accordance with commands from the controller (which also serves as a transport control means). Reference numerals 2a to 2C are paper feeding units that accommodate paper sheets (hereinafter referred to as print paper). Reference numeral 3 denotes a photosensitive drum, on which a latent image formed by an optical system (not shown) is formed by a known electrophotographic process, and is transferred onto printing paper by a transfer charger (not shown). A fixing device 4 fixes the toner image transferred to the print paper. A flapper 5 controls the direction of the printed paper being conveyed.

6 is the paper output tray, and the print paper on which image formation has been completed is placed in i.
f! 24.

Reference numeral 11 denotes a duplex unit, which includes an intermediate tray 11a for reversing the print paper conveyed downward by the drive of the flapper 5, and duplex conveyance paths 14a and 1 that serve as conveyance paths for double-sided printing.
4b, etc., there is a sensor 12 for detecting the presence or absence of print paper stacked on the intermediate tray 1]a, and a sensor 12 for smoothly refeeding the print paper discharged to the intermediate tray 11a. A movable member 13 is provided for the purpose. Double-sided conveyance path 14a.

? 4b forms a feed bank conveyance path. Note that the print paper is transferred from the double-sided conveyance path 14a to the intermediate tray 1.
The photosensitive drum 3 is conveyed via the double-sided conveyance path 1a-14b to the photosensitive drum 3, which serves as an image forming section.

Reference numeral 15 denotes a paper refeed roller, which refeeds the print paper for double-sided printing once placed on the intermediate tray 11a to the double-sided conveyance path 14b according to a command from the control unit 1a, and stops the print paper at position iA. A D-cut roller 16 conveys the print paper placed on the intermediate tray 11a to the position of the paper refeed roller 15.

FIG. 2 is an enlarged view of the main parts of FIG. 1, and the same parts as in FIG. 1 are given the same reference numerals.

As can be seen from this figure, the member 13 is connected to the intermediate tray 11.
When a is in the paper discharge state, that is, the print paper is in the duplex conveyance path 14.
When being transported from a, move to position C in the diagram,
When the intermediate tray 11a is in the paper refeeding state, it moves to position B in the figure and presses the print paper from above. In this way, member 13
moves around axis P as a fulcrum.

When the control section 1a of the printer main body 1 receives a command from an external device, only one sheet of print paper is fed from one of the paper feeding sections 2a to 2c. Note that when printing at the highest throughput, the next print paper is fed after the currently fed print paper + a predetermined paper interval. Thereafter, a toner image, which is a visualized latent image formed on the photosensitive drum 3 by a known electrophotographic process, is transferred onto the fed print paper, and the fixing device 4 fixes the toner image onto the print paper. This completes the single-sided image formation on the print paper. Print paper on which one-sided image formation has been completed.

In order to perform double-sided printing, the flapper 5 guides the paper to the double-sided conveyance path 14a. After that, the paper crosses the sensor 12 and is once stacked on the intermediate tray 11a. When the stacking is completed, the paper is fed to the double-sided conveyance path 141 by the paper refeed roller 15, and is conveyed to position A in the figure and stopped. ). Then, wait for instructions from the external device,
It depends on the paper size of the set-up print paper, but in the case of relatively small paper size (A4 or less), in order to maintain the specified paper interval, the next paper after the set-up print paper is also fed by the paper refeed roller 15. The paper must be re-fed onto the duplex conveyance path 14b.

However, in reality, since the intermediate tray 11a is used for stacking print sheets, the sheets are not re-fed and the paper interval becomes longer.

Therefore, the feeding of print paper is controlled by the control procedure shown in FIG.

FIG. 3 is a flowchart showing an example of paper feeding control for print paper according to an embodiment of the present invention.

Note that (1) to (10) indicate each step. Also the third
The control unit 1a shown in the figure is called at regular intervals by the control unit 1a shown in FIG.

When paper feeding control in the first mode (single-sided print mode) is called, it is determined whether or not paper feeding is possible (paper feeding possible flag=1) with reference to the paper feeding possible flag (1).

If this judgment is YES (it is automatically YES when printing starts), check the ready condition of the printer body 1 (if it is ready, there will be no errors and you can print immediately),
Then, it is determined whether or not to print from an external device (2). Here, if No, the control ends if the printer is not ready or there is no intention to print from the external device, and if YES, the paper feed section specified by the instruction from the external device, etc. For example, paper feeding is executed from the paper feeding section 2a, and a paper feeding execution routine is performed to determine the time "ro l Tl" described later according to the paper size of the printed paper (3). Then, it is determined whether the fed print paper is to be conveyed to the duplex unit 11 (4), and if No, a timer TA (not shown) is set to have no time To (described later). set to the condition (
5) Start timer TA and set the paper feed ready flag to "
0'' and the control ends (6). Note that when the paper feeding flag is "0", it means that paper feeding is not possible. Also timer TA
counts for a time proportional to the set value, and indicates that counting is in progress/counting has ended. However, time T1
may be substantially rOJ.

Next, even if the flow shown in FIG. 3 is called, if the judgment in step (1) is No, it is judged whether the timer TA has timed up (7), and if No, the control is terminated and the previous print paper is After feeding the paper, repeat steps (1) and (8) until the predetermined time has elapsed), YES
If so, the paper feeding enable flag is set to "1" (8), the process returns to step (2), and paper feeding is performed based on the intention of the external device.

By repeating the above operations, continuous single-sided printing can be performed at a desired throughput (number of printable sheets per minute) depending on the external equipment. However, the maximum throughput is determined by the printing operation speed of the printer body 1, and in order to achieve the maximum throughput, the timer TA is set to a time To that satisfies the following equation (3).

To = TP + TX' --
(3) However, Tp indicates the time for the paper width of the print paper, and TX indicates the time for the paper interval to achieve the maximum throughput. Therefore, in the case of single-sided printing, the next print paper can be fed after this TO time, so if the control section 1a performs control appropriate to that timing in response to commands from the external device, maximum throughput can be achieved. Continuous printing is possible.

On the other hand, if the determination in step (4) is YES, that is, in the second mode (in the case of double-sided printing), the printed paper fed from the intermediate tray 11a and reversed after image formation on one side is was set up at position A on the double-sided conveyance path 14b (9). If NO, return to step (5); if YES, time T1 obtained in step (3) was added to time TO. value to timer TA
(io), return to step (6), and repeat the same operation as for single-sided printing.

In this way, the paper feeding timing from the intermediate tray 11a is delayed from the maximum throughput, and the paper feeding timing from position A onward is at time T.

controlled by Note that the setup completion state is latched until the print operation is completed.

Therefore, until it becomes possible to print on the back side, the interval between print sheets fed from the intermediate cassette is extended to time T1, and thereafter, until the printing operation is completed, the interval returns to the interval between sheets at the maximum throughput.

This time T1 may be set to the time from the start of paper refeeding of the intermediate tray 11a to the time when the print paper is received and delivered to the paper refeed roller 15. That is, after the first sheet of paper conveyed to the duplex conveyance path 14a is stacked on the intermediate tray 11a, the refeeding of the first sheet of print paper has finished before stacking of that sheet of paper starts. ing. Then, by the time the stacking of the third sheet of paper begins, after the second sheet of paper is stacked, the paper is immediately re-fed, follows the first sheet of paper, and stops after reaching the paper spacing position that provides the highest throughput. .

Therefore, once the double-sided printing paper is set up, double-sided printing can be performed at maximum throughput based on instructions from an external device. However, the external device is not limited to feeding paper from the duplex conveyance path 14b or from the paper feed units 2a to 2C, but can feed print paper randomly from both, and can feed single-sided print paper and duplex paper at the highest throughput. Print paper is ejected in a mixed state.

In the above embodiment, the setup completion position was set at position A shown in FIG.
4b or anywhere in the printer body 1.

Furthermore, in the above embodiment, the completion of setting up the double-sided print paper was managed at the position A shown in FIG.
It may also be managed by the number of sheets of printed paper conveyed.

Furthermore, in the above embodiment, the time TI to be added to the timer TA
We have explained the case where the paper size is determined according to each paper size, but even if the paper size is the same, both sides (feeding paths 14a, 14b
The pitch may be varied randomly or at a fixed pitch depending on the number of sheets of printed paper conveyed.

Further, in the embodiment described above, a case has been described in which the interval between printed sheets is determined according to the time TI added to the timer TA, but the interval between printed sheets may be determined using a sensor or the like in the conveyance path.

Furthermore, in the above embodiment, the case is explained in which the duplex paper is latched from the time the set-up is completed until the print operation is completed, but the set-up completion is set/reset according to the sensor etc. without latching the side stage. All you have to do is
It doesn't matter where you change the latch timing.

Further, in the above embodiment, the intermediate tray 1 of the duplex unit 11
Although we have described the case where the paper spacing between printed sheets is adjusted due to the constraints of 1a, in a recording apparatus that can be attached with a paper ejection means such as a sorter, a paper ejection means other than the printer main body 1 (
The present invention can also be applied to the case where the paper spacing between printed sheets is adjusted according to the constraints of external means.

Furthermore, although double-sided printing has been described in the above embodiment, it goes without saying that the same method may be used for multiple printing.

〔Effect of the invention〕

As explained above, the present invention provides a conveyance control means that extends the refeeding interval of paper sheets conveyed through the double-sided or multiplex conveyance path-L according to the conveyance state of the paper sheets or the state of the external means. Because of this provision, the paper interval between the paper sheets conveyed from the duplex conveyance path can be freely adjusted, thereby improving throughput, and even if the operation of the duplex conveyance path becomes slow, the maximum throughput of the printer main body will not be reduced. It has the excellent advantage of being able to print continuously without any problems.

[Brief explanation of drawings]

Fig. 1 is a sectional view illustrating the outline of a recording device showing an embodiment of the invention, Fig. 2 is an enlarged view of the main part of Fig. 1, and Fig. 3 is a printed paper showing an embodiment of the bird invention. 3 is a flowchart showing an example of paper feeding control. In the figure, 1 is the printer main body, 2a to 2C are paper feed units, 3 is a photosensitive drum, 4 is a fixing device, 5 is a flapper, 6 is a paper output tray, 11 is a duplex unit, 1]a is an intermediate tray, 12 is a sensor, 13 is a member, 14a and 14b are double-sided conveyance paths,
15 is a paper refeed roller, and 16 is a D-cut roller. Figure 1 1゛ Printer body Figure 2 [7C Figure 3

Claims (1)

[Claims] It has a double-sided or multiple conveyance path that refeeds the paper sheet to the image forming unit after being reversed or not, and the paper sheet is selectively reversed or is not reversed. In a recording device that forms images on both sides or multiple on one side of a sheet, the refeeding interval of the sheet conveyed on the duplex or multiple conveyance path is determined according to the conveyance state of the sheet or the state of external means. A recording device characterized in that it is equipped with a conveyance control means that extends the length of the recording device.