JPS63102971A - Print density detector - Google Patents

Abstract

PURPOSE:To suppress degradation of printing efficiency to the minimum, in an impact printer, by detecting the print density for every specific printing times and determining the specific printing times corresponding to the detected value. CONSTITUTION:The print density on a banknote 20 is detected through an image sensor 9 by means of reflected light from a light source 21, and inputted through an inverting amplifier 10, a samplehold 11 and an A/D converter 12 to a comparator 13. On the other hand, a controller 14 consisting of a microcomputer controls a counter to count up the printing times for every printing of banknote, and upon reaching a specific printing times, a reference value is inputted into the comparator 13 and compared with the detected density, and abnormal processing is carried out when the print density level lowers below the reference level. The specific printing time is set according to the detected print density level such that it is smaller as the print density approaches the referential level. (e.g. 1,000, 500...50, 10). Consequently, the replacing time of ink ribbon can be decided accurately without sacrifice of the printing efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Al Industrial Application Field) This invention relates to a print density detection device for detecting the print density of an impact printer and determining when to replenish or replace ink.

(b1 Summary of the Invention The print density detection device according to the present invention detects the print density by scanning the print surface of an impact printer every specific number of times corresponding to the print density. By setting the number of times proportionally, the decrease in print processing efficiency is minimized, and the sensor can accurately determine the print density.

(C) Prior Art An impact printer is equipped with an ink ribbon, an ink roller, etc. as an ink supply source, and transfers the ink impregnated in the ink supply source to a printing surface directly or via a print head. As the ink impregnated in the ink supply source decreases, the print density gradually becomes lighter (.

As a device equipped with an impact printer, for example, A
There are passbook printing machines installed in TMs (Automated Teller Machines), etc. It is equipped with a passbook printing machine and an ink ribbon, but if the print density becomes too light, it becomes difficult for the customer to check the transaction results. There was a risk that the transaction results would be printed out.

(d1 Problems to be Solved by the Invention) For this reason, conventional bankbook printing machines have adopted the following print density detection method.

■A method that detects the print density by scanning the print surface with a sensor every time it is printed (optical method).A method that warns you to replace the ink ribbon when counting the number of times that the print density is generally considered to be low (software method). Here, method (■) has high detection accuracy because it directly scans the printing surface to detect the print density, but it requires scanning for detection in addition to scanning for printing, and the time required to print a passbook is almost This has the drawback of reducing the operating efficiency of the ATV by twice as much.

In addition, method (■) does not extend the time required to print a passbook, but because it counts uniformly regardless of the printed content, it cannot deal with ink consumption that varies for each print or variations in the amount of ink impregnated in the ink ribbon. There are defects and bad printing (
In order to prevent low-density printing, a warning must be given to replace the ink ribbon well in advance, which has the disadvantage of wasting ink.

This invention was made in view of these conventional drawbacks, and it is possible to detect print density with high precision without reducing processing efficiency by performing highly accurate print density detection using an optical method every specific number of times of printing. The object of the present invention is to provide a print density detection device that can perform the following steps.

(Means for solving the e1 problem) This invention was made in consideration of the characteristic that impact printers use ink supply sources such as ink ribbons and ink rollers, and the print density gradually becomes thinner. In a print density detection device having a sensor that scans a print surface printed by a printer and detects the print density, a print number counter is provided to count the number of prints by the impact printer, and the print number counter counts a specific number of times. means for operating the sensor each time the sensor is activated;
The present invention is characterized in that it further includes count number determining means for determining the specific number of times in response to the print density detection value of the sensor.

(f1 action) In the print density detection device of the present invention, the sensor detects the print density on the print surface every time the print count counter counts a specific number of prints, and the specific number of times is determined in accordance with this print density. .Furthermore, if the print density has decreased below a predetermined density, a corresponding process is performed.If normal, the print process returns to normal print process.On the other hand, print density is not detected in normal print process.

(g) Embodiment FIG. 2 is a schematic structural diagram of a bankbook printing machine to which a print density detection device according to an embodiment of the present invention is applied. Passbook insertion slot 1
A passbook transport path 2 is formed from the inside of the device toward the inside of the device.

A plurality of pairs of conveyance rollers 3 are provided up and down along this passbook conveyance path 2.
is installed.

Also, a thickness sensor 4 is installed near the passbook conveyance path 2 from the passbook insertion slot 1 side. Print head 5a, platen 7, passbook sensor 6, image sensor 9. A page turning device 8 is installed. The thickness sensor 4 consists of a pair of rollers, and detects the thickness of the passbook by the opening of the rollers when the passbook passes. The print head 5a is a head of the wire dot printer 5, and an ink ribbon (not shown) is attached to the print head 5a. Platen 7
is opposed to the print head 5a. The passbook sensor 6 is for detecting the leading edge of the passbook when printing the passbook. The image sensor 9 is for scanning the print surface of the passbook transported to this position and detecting the print density. The page turning device 8 is for turning over a printed page and opening the next page.

FIG. 3 is a block diagram of a print density detection device including the image sensor 9. As shown in FIG. The reflected light from the light source 21 on the printed surface of the bankbook 20 enters the image sensor 9 . Image sensor 9 is connected to preamplifier 10. Preamplifier 1
0 inverts and amplifies the input detection output of the image sensor 9. In other words, if the printing density on the printing surface is dark < (the level of reflected light is low ()) and the detection output of the image sensor 9 is low, a high voltage is output; If it is high, a low voltage is output.The output of this preamplifier 10 is hereinafter referred to as "print density".The print density is input manually to the sample hold circuit 11.The sample hold circuit 11 outputs one line of the print field (print surface). The stored print density is input to the A/D converter 12, converted to a digital value, and input to the comparator 13.The comparator 13 receives a reference value from the microcomputer 14. is input, and the print density is compared with this reference value to determine whether it is normal printing or defective printing.The reference value is set to the lowest value of the print density of normal printing, and is digitally converted. When the print density falls below this reference value, predetermined processing is performed as a defective print.

The microcomputer 14 inputs a reference value to the comparator 13 to enable its operation, and also communicates with other control units (for example, the control unit of a passbook printing machine, etc.) to control the timing for performing the print density detection operation. do. In the memory of the microcomputer 14, a printing number counter for counting the number of times the passbook printing machine prints a passbook is set, and a printing temperature-counting number correspondence table shown in the table below is also set.

Table 1 is a flowchart showing the operation of the microcomputer 14. Step nl (hereinafter, step n
Simply say i as ni. ), when the electronic message indicating that the passbook printing has been performed is received from the controller 4!1 of the passbook printing machine, the printing number counter is incremented (n2). If the count up has reached the count expiration value, n3 will determine
Perform the following actions. If the count has not reached the expiration value, return directly.

At n4, the reference level value is input to the comparator 13 to make a print density judgment, and if the judgment result is normal, the print density counter is cleared and the process returns. If the print density is below the reference level, the process advances to n7.

At n7, it is determined whether the detected print density is less than level 2, and if it is 2 or more, the column corresponding to the print density is searched from the table, a new reference level and count expiration value are set ( n8), reset the counter (n9
) Return. If the detected print density is less than level 2, the process proceeds to abnormality processing (nlo), and returns when the ink ribbon is replaced by the staff member (nil) and the table is reset (n12).

n2. n3 corresponds to the "means for operating a sensor every specific number of times of printing" of the present invention, and the table and n7. n
8 corresponds to the "means for determining a specific number of times in response to a print density detection value" of the present invention (h) Effect of the invention According to the present invention, highly accurate optical type print density detection is used to determine a specific number of times of printing. By performing this every time, it is possible to accurately detect the print density and accurately judge when it is time to replace the ink supply source such as the ink ribbon. This makes it possible to eliminate defective prints with poor legibility. Furthermore, by detecting print density every specific number of times of printing and determining the specific number of times based on the detected value of print density, it is possible to make the interval between print density detections extremely long when the print density is sufficiently high. When the print density approaches 4 (defective value), the detection interval can be narrowed to accurately determine when it is time to replace the ink supply source.
Decrease in printing processing efficiency can be minimized.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the operation of the control section of a print density detection device according to an embodiment of the present invention, FIG. 2 is a schematic structural diagram of a passbook printing machine to which the print density detection device is applied, and FIG.
The figure is a block diagram of the print density detection device. 5-printer, 5a-print head, 9-image sensor, 13-comparator, 14-microcomputer. Outsourcer Tateishi Electric Co., Ltd.

Claims (2)

[Claims] (1) Scan the printing surface printed by the impact printer,
In the print density detection device having a sensor for detecting the print density, a print number counter is provided for counting the number of prints by the impact printer, and means for operating the sensor each time the print number counter counts a specific number of times. ,
A print density detection device comprising: count number determining means for determining the specific number of times in response to a print density detection value of the sensor. (2) The print density detection device according to claim 1, wherein the count number determining means includes a table that associates print density detection values with count numbers.