JP3097705B2 - Printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer for automatically adjusting a gap between a sheet and a print head.

[0002]

2. Description of the Related Art In a serial printer, especially a wire impact type printer, it is essential to always maintain a proper gap between the paper surface and the leading end of a print head in order to ensure good printing and prevent damage to a printing mechanism. It is a procedure that cannot be done. For example, if the gap is too wide, sufficient printing pressure cannot be applied to the ink ribbon and the paper. If it is too narrow, the print head may catch the ink ribbon or the edge of the paper.

For this reason, a plurality of mechanisms have been invented which measure the thickness of the printing paper or the position on the surface of the printing paper, and automatically move the position of the head based on the measurement result so that the gap becomes appropriate.

In a conventional printer that automatically adjusts the gap, each time one sheet of paper is fed, the surface position of the sheet is measured, and the head is moved to a position separated from the surface by an appropriate gap. .

[0005]

However, since the operation of measuring the paper thickness requires very fine positional accuracy, it may take considerable time depending on the measuring method.

[0006] When printing continuously on a plurality of cut sheets using the CSF, the sheet thickness is measured for each sheet, but the cut sheet used in the CSF has at least one continuous sheet. It is common sense to use paper of the same standard while printing a document. Therefore, if the paper thickness is measured each time the paper is fed, the throughput is considerably reduced as compared with a printer having no measuring function. In particular, as the printing speed and the paper feeding speed are higher, the ratio of the paper thickness measurement time to the total printing time increases, and the rate of decrease in throughput increases.

The present invention has been made in view of the above problems, and has as its object to reduce the number of sheet thickness measurement operations involved in sheet feeding from the CSF within a safe range as much as possible and to improve throughput. I do.

[0008]

Means for Solving the Problems To achieve such a problem
Therefore, according to the present invention, the recording paper is supplied to the printing mechanism.
Paper feed means for feeding paper and recording paper arrived at the printing mechanism
Paper detecting means for detecting that
Paper thickness measuring means to determine the platen gap
Gap adjustment means for adjusting the gap and initialization after turning on the power
During operation, a paper out error was output by the paper detection means.
Time or waiting for external data
Cleared by any of the
Storage means for storing the paper thickness measured by the setting means;
The paper thickness measuring means when the storage means is cleared;
And control means for operating the gap adjusting means.
I prepared for it.

[0009]

[Operation] It is determined whether or not the storage means is cleared,
If it is cleared, activate the paper thickness measurement
Measure the thickness and store the measurement result.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the configuration of a printer according to this embodiment.
As shown in FIG. 1, this printer is a so-called flatbed printer. In the figure, 1 is a print head, 2
Is a paper detector by a reflection type optical sensor, 3 is a first bin of CSF, 4 is a cut sheet fed from the first bin, 5 is a CSF
The second bin 6 is a push-type tractor sprocket.
7 is a continuous form paper attached to the tractor sprocket,
Reference numerals 8 to 11 denote paper feed rollers, reference numeral 12 denotes a flat platen, and reference numeral 13 denotes a carriage for moving a print head. Reference numeral 14 denotes a first carriage shaft to which the carriage is attached, which is attached so as to be able to rotate around a + mark eccentric to the center of the shaft. Reference numeral 15 denotes a second carriage shaft fixed at a fixed position, and the carriage 13 is attached to the second carriage shaft 15 with a margin for moving up and down.

FIG. 2 shows the construction of the paper thickness measuring and gap adjusting mechanism of the printer. In the figure, a first carriage shaft 14 is rotated by a gap motor 16. As described above, the center of rotation of the first carriage shaft 14 is shifted from the center of the shaft, and the carriage 13 is attached to the second carriage shaft 15 with a space above and below the shaft so as to be able to move up and down. Therefore, the carriage 13 moves up and down according to the rotation angle of the gap motor 16.
When the gap motor rotates in the CCW direction as viewed from the front of the figure, the carriage 13 is lifted, and when rotated in the CW direction, the carriage 13 is lowered.

A rotary encoder 17 is attached to the gap motor 16, and the position of the carriage 13 in the vertical direction can be confirmed by an output signal.

FIG. 3 shows the configuration of the control circuit section of this embodiment. 100 is a control means for controlling each means. 101
Is a paper thickness measuring means for measuring the distance from the maximum gap position to the paper surface in accordance with a command from the control means 100 and returning the measurement result to the control means 100.
And a circuit for controlling the rotary encoder 17 and software. Reference numeral 102 denotes a gap adjusting unit that moves the carriage 13 up and down to an appropriate gap position designated by the control unit 100, and controls the gap motor 16 and the rotary encoder 17. Reference numeral 103 denotes a storage unit that causes the control unit 100 to store the measured number of steps to the surface of the sheet as sheet thickness data. 104 is an input data buffer for storing the data transferred from the external machine.
M. Reference numerals 105 and 106 denote a “paper feed” button and a “paper selection” button on the operator panel, respectively, and output their states to the control means 100. Reference numeral 107 denotes a sheet selection unit that switches a sheet to be used according to a command from the control unit 100. Reference numeral 108 denotes a timer that outputs a time-up signal to the control unit 100 after a lapse of a predetermined time from the reset by the control unit 100. The paper detector 2 is also monitored by the control means.

Here, the outline of the paper thickness measurement and the gap adjustment will be described. The measurement of the paper thickness is performed by moving the carriage 13 downward from the widest gap position while monitoring the signal of the rotary encoder 17 with the paper inserted under the head 1. The number of steps from the output of the rotary encoder 17 until the tip of the head 1 hits the paper to be measured and the movement of the carriage 13 is detected from the output of the rotary encoder 17 is defined as the position on the surface of the paper. Gap position adjustment is performed from the measured paper surface position to a position wider by the predetermined appropriate gap.
The movement is completed by moving the carriage 13.

In this embodiment, attention is paid only to the measurement of the paper thickness of the first bin of the CSF. The following five cases are assumed in this embodiment when “a sheet having a thickness different from the previous time is fed”.

(A) While the power was turned off, the cut sheets in the first bin were replaced and the power was turned on again.

(B) After the paper selection is switched from the first bin of the CSF to another paper such as a second bin or a tractor, the cut in the first bin is replaced and the CS is returned again.
The F1 bin was selected.

(C) While the input of print data from the external machine is interrupted, the cut sheet in the first bin is replaced and printing is restarted.

(D) The paper in the first bin runs out, and another cut sheet is stored.

(E) After the paper in the first bin runs out during printing, another paper is stored, and a manual paper feeding operation is performed as a command to restart printing.

The above 5 is not independent, and if one occurs, it may be unavoidable that another occurs. However, in order to increase the certainty, the paper thickness is measured even if one of the five occurs. Do it again.

How the above determination is realized in the printer of this embodiment will be described with reference to the flowchart of the control means.

FIG. 4 shows a flow chart when paper is fed from the first bin 3. An operation of sending a cut sheet from the first bin 3 to the paper detector 2 is performed (step 401), and it is determined whether the paper has actually reached the paper detector 2 (step 40).
2) If there is no paper, it is determined that there is no paper in the first bin 3. This corresponds to the above (d). Then, the storage unit 103 is cleared to 0 (step 403), and the printer is set to a paper-out error state (step 404), and the processing ends.

On the other hand, if there is paper in step 402, the paper is further fed to a predetermined cueing position (step 405), and the value in the storage means 103 is read (step 406). If the value is 0, it instructs the paper thickness measuring means 101 to measure the paper thickness (step 407). Then, the result is referred to as gap adjusting means 1.
02 to obtain an appropriate gap (step 408).
If the content of the storage means 103 is not 0, the value is passed to the gap adjustment means 102 as it is (step 408). Further, the paper-out error is released (step 409), and the process ends.

As described above, the storage means 103 normally holds the latest paper thickness measurement data, and clearing this data to 0 makes a re-measurement request.

FIG. 5 shows the processing after the power of the printer is turned on. Here, the storage unit 103 is cleared to 0 as a part of the initialization operation (step 501). This corresponds to the case (a) described above.

FIG. 6 shows the processing of a data waiting loop in a non-printing state. First, the timer 108 is reset (step 601), and the process enters a data waiting loop. It is determined whether or not there is data in the input data buffer 104 (step 602). If there is data, the process exits the loop for data processing and ends (step 603). On the other hand, if there is no input data in step 602, the output of the timer is read (step 604). If the time is up, the storage unit 103 is cleared (step 60).
5). This corresponds to the case (c) described above. Subsequently, the panel buttons are scanned and processed (step 606).
After the panel operation, the process returns to step 602 and loops until data is input.

FIG. 7 shows the operation of the panel operation. It is determined whether or not a sheet other than the CSF bin 1 is selected by the sheet selection button 106 (step 70).
1) If other than CSF bin 1 is selected, storage means 1
03 (step 702), and the sheet selecting means 10
7 and switch to that sheet (step 703).
This corresponds to the case (b) described above. Then, the processing jumps to the processing flow for the paper (step 704), and the CSF
Exit from the processing of the first bin.

If it is determined in step 701 that the first bin of the CSF is selected, it is determined whether or not a paper feed is requested by the paper feed button 105 (step 705). If there is a request and there is no paper (step 7
06) Clear storage means 103 (step 70)
7). This corresponds to the case (e) described above. Then, the above-described sheet feeding operation is performed (step 708), and the process ends. If the paper is not present in step 706, no paper can be fed, and the process ends without doing anything.

Finally, FIG. 8 shows the automatic paper feeding accompanying printing.
Shown in

First, it is determined whether or not there is paper (step 801). If there is paper, one line is printed and the process is terminated (step 805). If there is no paper, the above-described paper feeding operation is performed (step 802), and it is determined whether or not there is paper (step 803). If there is paper, printing is performed (step 805). If there is no paper, the above-described panel operation processing starts (step 804), and it is checked whether the paper feed button 105 and the paper selection button 106 have been pressed. When the paper selection is changed, the process jumps directly to the printing process for another paper and exits from the flowchart in FIG. Otherwise, the process returns to step 803 again. Paper feed button 10
This loop is continued until the feeding of the sheet 5 is attempted and succeeded, and printing is performed when a new cut sheet is fed (step 805).

As described above, in this embodiment, attention is paid to only one bin. However, other bins can be handled by providing a plurality of the configurations of this embodiment.

In this embodiment, a printer including all the contents described in the claims has been described. However, it is of course possible to omit the contents of unnecessary items according to use conditions. In addition, in the contents described in claim 2, that is, in the embodiment that does not include (a) in the present embodiment, the storage means (103 in FIG. 3 of the present embodiment) stores data in a non- It is necessary that the storage means be sexual.

[0035]

As described above, the present invention provides a method for remeasurement of paper thickness.
The necessity was determined based on the presence or absence of data in the storage means.
Therefore, the throughput can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a print head and paper feed mechanism of a printer according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a mechanism for measuring a paper thickness and adjusting a gap of the printer according to the embodiment of the present invention.

FIG. 3 is a block diagram of a control unit of the printer according to the embodiment of the present invention.

FIG. 4 is a flowchart of paper feeding of the printer according to the embodiment of the present invention.

FIG. 5 is a flowchart when the power of the printer according to the embodiment of the present invention is turned on.

FIG. 6 is a flowchart of a data waiting loop of the printer according to the embodiment of the present invention.

FIG. 7 is a flowchart of a panel operation of the printer according to the embodiment of the present invention.

FIG. 8 is a flowchart of automatic paper feeding at the time of printing by the printer according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head 2 Paper detector 12 Platen 13 Carriage 16 Gap motor 17 Rotary encoder 100 Control means

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Claims (1)

(57) [Claims] A feeder for feeding recording paper to a printing mechanism; a paper detector for detecting that the recording paper has reached the printing mechanism; and a paper thickness measuring means for measuring the thickness of the recording paper. A gap adjusting means for adjusting a platen gap according to the paper thickness; a predetermined time in an initializing operation after power-on, when a paper-out error is output by the paper detecting means, or in a state of waiting for external data. Storage means for storing the paper thickness that has been cleared by any of the elapsed times and measured by the paper thickness measurement means, and when the storage means has been cleared, the paper thickness measurement means and the gap adjustment means And a control means for operating the printer.