JPH02171776A - Paper passing control system - Google Patents

Abstract

PURPOSE:To accomplish a high speed printing action and to improve utilizing efficiency by controlling the paper passing action corresponding to the input state or the accumulation state of information which should be printed in accordance with the number of sheets of paper which is held inside a conveying means and being inverted. CONSTITUTION:Communication time when data from a host computer 1 is inputted in a controller 2 is counted by a communication time counter 20 so as to grasp the state. The inputted data is accumulated in a memory 21 every page and how many pages are used for the memory at such a time is detected by a memory capacity detection part 22. The data is transferred from the host computer 1 to a printer and a paper passing mode is switched by taking the communication interval of the data and the real use quantity of the capacity of the memory as reference. Thus, average waiting time till printing is shortened, the high speed printing action is accomplished and the utilizing efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is directed to an image forming apparatus such as a laser printer or a copying machine, in which a printed sheet is reversed.

The present invention relates to a paper passing control method for a double-sided printing device that prints again on the reversed side. In particular, it relates to a paper passing control method for minimizing the amount of paper remaining in the device.

(Prior Art) FIG. 1 shows a block diagram of the control section of a laser printer as an example of implementing the present invention, in which data (D) from a host computer 1 is converted into a video signal (VI) by a controller 2. However, this video signal is converted into a laser beam by the printer control section 3, formed into an image by an electrophotographic process, and recorded on paper.

The double-sided printing device 4 and other loads 5 are controlled by the printer control section 4, and paper feeding control, which is the object of the present invention, is performed on the double-sided printing device 4.

The controller 2 also includes a communication time counter 20, a memory 21, a memory capacity detection unit 22, etc., and counts the communication time between the host computer 1 and the laser printer, detects how many pages are being used in the memory 21, etc. It has the following functions.

FIG. 2 shows an overview of the functional configuration of the double-sided printing device 4. As shown in the figure, the sheets stored in the paper feed cassette A are conveyed by the conveying means to the printing portion B without stopping the sheets one by one.

Then, in response to an instruction from the controller 2, the printer control unit 3 can independently stop the conveyance in each of the reversing conveyance paths C and D, and can switch the conveyance direction of the conveyance path. can.

The paper sheets printed on both sides are stored in a paper discharge tray E.

To explain the movement of paper, paper cassettes A to 1
The sheets fed two sheets at a time are printed on one side (front side) in the printing portion B, and then stop at the positions of the reversing conveyance paths C and D, respectively. Next, the paper is fed from the reverse conveyance path, and since the first paper passes through the printing portion B again here, it is printed on the other side (m side), resulting in so-called double-sided printing.

Subsequently, when the third sheet of paper reaches printing area B from paper cassette A, the first sheet, which has already been printed on both sides, is ejected to paper ejection tray E and transported in the direction of reversing conveyance path C. It is designed so that it will not happen. Then, the third sheet of paper is conveyed in the direction of the reverse conveyance path C, and the second sheet of paper reaches the reverse conveyance path during this time.

With this movement of the paper, the paper is alternately fed from the reverse conveyance path of the paper feed cassette A9, and double-sided printing is performed.

(Problem to be Solved by the Invention) The data flow when, for example, 10 pages of data are printed on 5 sheets of paper (2 pages on each sheet) in the double-sided printing device, that is, the data input to the printer. Order (a)
The data order (b) to be printed becomes the relationship shown in FIG. 3 (1) under the control of the controller 2. That is, here, the controller 2 performs the printing operation as shown in (b) when the pages are arranged and stored in the paper discharge tray E in order from the bottom to the top (hereinafter referred to as the F mode).

As you can see from the above, pages 1 and 2, pages 3 and 4, etc. are printed as pairs, and pages 9 and 10 are printed respectively, so the printing procedure is as shown in Figure 3 (2). When a pair is established for the data input to the printer (,), the printing operation (
c) will be performed, resulting in a considerable delay.

When processing continuous data from the host computer 1, this printing operation is performed continuously, so it does not take much time and does not bother the operator much, but if the data is processed intermittently, If you are
Since data is stored in the memory 21 until printing is performed continuously, there is a drawback that it takes time to print.

In addition, as the paper feeding method described above, instead of stopping the paper at the position of the reversing conveyance path C, the paper fed from the paper cassette A stops at the position of the first reversing conveyance path, and the first sheet starts from this position. An operation in which paper is fed and discharged to the paper discharge tray E is also possible. (Hereinafter referred to as F2 mode) In this case, the printing operation order is also simple, as shown in FIG. 3 (3). However, in this F2 mode, printing part B
Since the printing operation is not performed while the paper printed at the position is being conveyed from the reversing conveyance path C to D, there is a problem in that the usage efficiency of the printer is apparently halved.

The present invention does not require the operator to set the two paper feeding modes F□ and F2 in advance, but rather determines how to speed up the printer's printing operation and improve usage efficiency from the data input state or data memory usage state. The purpose is to perform appropriate paper feeding control.

(Structure and operation) In order to achieve the above-mentioned object, the present invention uses at least two or more independently operable conveyors to transport the paper when the paper that has been printed once is reversed and printing is performed again on the reversed surface. For a double-sided printing device having a means, the number of sheets being reversed held inside the conveying means controls the paper feeding operation according to the input state of information to be printed or the accumulation state of print fill information. It is characterized by

According to the present invention, the controller determines whether to use the F mode or the F2 mode depending on the input state or storage state of information to be printed, thereby speeding up the printing operation and improving usage efficiency.

(Embodiment) In the present invention, the control unit of the printer (FIG. 1) controls paper passing through the double-sided printing device 4 as follows.

Data from the host computer 1 (FIG. 4) is input to the controller 2, and the communication time is counted by a counter 20 to grasp the state. Also, the input data is stored page by page in the memory 21, but how many pages are being used in the memory at that time?

The memory capacity detection unit 22 detects whether or not the data is stored.

Therefore, the first method of this embodiment is to use the data communication interval, and the second method is to use the actual amount of memory capacity used.

(First embodiment) Figure 4 shows an example of data input from the host computer as described above, where (1) is the case where the data is continuous, and (2) is the case where the data is intermittent. In this case, there are cases where the page interval is within two pages.

Here, the paper passing mode corresponding to (1) is naturally the F8 mode, but in the case of (2), the data ratio is the criterion.

Now, assume that the processing ratio (printing speed ratio) between F□ mode operation and F2 mode operation of the printer is 2:1.

The data ratio corresponding to this is 50%. If the data ratio is 50% or more, it cannot be processed in the F2 mode and the data is simply stored in the memory 21.

Therefore, if the data ratio is 50% or less regardless of the nine pages between pages, the F2 mode is selected. The controller 2 determines whether the data ratio is 50% by checking the communication time counter 20 for communication/non-communication.
This is done by calculating a weighted average of the counter values.

(Second Embodiment) The first embodiment described above uses the data communication interval, but this embodiment uses the actual usage area of the memory capacity. Here, the determination of whether to operate in the F or F2 mode is based on how many pages have been viewed, rather than the absolute amount of area in the memory 21 (buffer).

When operating in F□ mode, at least 3 pages (4 pages including the page currently being written) are required. However, the contents for two pages are simply stored for waiting for the turn to be printed, and the latter one page is for receiving the next data.

Therefore, as shown in the flowchart of FIG. 5, the control of the controller 2 focuses on the above-mentioned state and determines whether or not reception of the next data has started at the end of a certain printing operation (a). Depending on whether the used buffer (memory 21) is 2 pages or 3 or more pages, it is determined whether to shift to F2 mode (B). In this example, the mode shifts to F2 mode after 2 pages [(B) NO].

Next, in the F mode, the data queue is for one page, so when a certain printing ends, the buffer used is 3.
If the number of pages exceeds that number, a determination is made as to whether or not to return to the F□ mode. In this example, it is determined whether to return to the F1 mode (dashed line arrow) (YES) depending on whether the used buffer is one page or two or more pages at the end of printing.

As a matter of course, the transition between the FY mode and the F2 mode may be performed by taking the average (force) of (1) and (E) after several printings and returning to the F□ mode.

(Effects of the Invention) As explained above, the present invention transfers data from a host computer to a printer, and the average waiting time until printing is determined based on the data communication interval and the actual amount of memory capacity used. Since the F2 mode is switched,
This makes the printing process faster and more efficient.

Furthermore, since the number of sheets of paper remaining in the printer decreases in the F2 mode, it becomes easier to recover from jams and the like.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control portion of a laser printer as an example of implementing the present invention, FIG. 2 is a schematic functional configuration diagram of the duplex printing device 4 shown in FIG. 1, and FIG. 3 is an operation of the duplex printing device 4. An explanatory diagram of mode F□I F2, Figure 4 is an example of data input from the host computer to the laser printer,
FIG. 5 is a flow chart for explaining the second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Host computer, 2...Controller, 3...Printer control unit, 4...Double-sided printing device, 5...Each load, 20...Communication time counter, 21...Memory (buffer) ), 22...Memory capacity detection section.

Claims (1)

[Claims] When a sheet of paper that has been printed once is reversed and printing is performed again on the reversed side, the sheet is held inside the conveyance means for a duplex printing apparatus having at least two or more independently operable conveyance means. A paper passing control method characterized in that a paper passing operation is controlled according to the number of sheets being reversed, an input state of information to be printed, or an accumulation state of information to be printed.