JPS61500110A - Print quality control device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Print quality control device Technical field The invention preferably uses a matrix or liquid jet printer with the aid of a photosensitive device. The present invention relates to a method and apparatus for inspecting the printing quality of a printer.

Background technology When printing with a matrix printer, reliability is mainly determined by the condition of the printing ribbon and the print head. depends on all printing elements of the printer being functional. Regarding the control of these functions A particularly obvious problem exists when the printer is used without continuous monitoring. do. An example of such a printer is a computer-controlled printer that operates at specific times during the day. A printing device or cash dispenser that prints out details of transactions carried out. Ru.

There are different ways to test the print quality of matrix printers. for example 'tpc'r application US81101207 describes an optical sensor that follows the print head. The tail describes the device that detects each dot printed by the sensor. The detection results are The computer compares the signal pattern with the signal pattern corresponding to the printed character. From the signal pattern A fault signal is generated due to the misalignment. This device is an ink-jet printer. It is also intended for use in data. There are two factors that affect the print quality of matrix printers. The most important factors are the condition of the printing ribbon and the function of the printing element, so the above patent The result is unnecessary elaboration and over-the-top solutions.

Disclosure of invention According to the invention, printing of a matrix printer or an ink jet printer A simple and effective inspection of quality can be carried out. This is done by normal printing. By simultaneously printing an f-dot pattern with each printing element in an area of the paper that is not will be done. The photosensitive element reads out the print pattern in conjunction with the row shift. in this way The generated signals are processed to create a predetermined signal pattern that corresponds to accurate print quality. compared to The difference between these patterns sets off an alarm circuit. Features of the present invention The features are disclosed in the appended claims.

Brief description of the drawing The present invention will be described in detail below with reference to the accompanying drawings, in which FIG. The parts of the matrix printer are schematically illustrated, and Figure 2 shows the electrical circuits involved. A roadside beggar is shown.

Best embodiment of the invention Figure 1 shows characters printed by two matrix printer type print heads. A printing paper 1 is schematically illustrated. The print head merges the left side of the paper for each line of print. This pattern also prints dot pattern 3 on the print head. It is formed as a right-angled draft row and is produced by all write elements of the printhead.

The photosensitive device 4 is arranged so that the dot pattern 3 passes under the photosensitive device during row shifting. The sea urchins are placed in the same direction.

FIG. 2 illustrates the device according to the invention in more detail. The photosensitive device 4 is, for example, E G&G reticon RLI28G type shift register 8 rows of photodiodes It includes a light emitting diode 7 for illuminating the lower printing paper. Dot row 3 during row shift moves past the photodiode array 8 in the direction of arrow P, where the diode They are spaced at a distance of 25 μm and are arranged at right angles to the direction of movement of row 3.

By means of a shift register, each diode is connected to a control device 12 included in the computer 6. are read out sequentially at a speed determined by In this case, the clock frequency of the control device is 5D KHz, the sampling frequency was selected as 300Hz, which is 2.56 ms scan time and about 12 scans per 30 dot pattern. Each light da The signal from the iode is transferred to a comparator 5, where it is amplified by a DC amplifier F, It is compared with the voltage from the reference voltage source R by a differential amplifier. of amplitude higher than the reference voltage. The signal is assigned a ``1'' by the differential amplifier, while the low amplitude signal is assigned a ``0''. Can be guessed. The digitized signal is read by a computer 6, where a counter 9 adds all "1"s according to the given conditions. For example, one condition is - The force counter requires a small number (all four consecutive "1"s) to add. That's what I mean. After 6 scans of all diodes without the above conditions being met , the counter is read and then set to zero. Dot passing through photosensitive device ・The condition for registering a dot when pattern 30 is passed is, for example, when counter 9 is counted 40 times. This means adding "1"k. The number of registered dots is register 0 and print head 2 mark. compared to the number of character elements.

If there is a difference between these signals, the bond circuit 11 is activated to provide an alarm signal.

International research report 111

Claims (5)

[Claims] 1. Preferably matrix or inkjet printer markings by photosensitive circuitry. In a method of checking character quality, the printer applies a predetermined The characters are printed, the characters are read by the photosensitive circuit in relation to the line shift, and the photosensitive circuit The signal pattern from the road is compared with the signal pattern that corresponds to correct reproduction of the printed characters. The photosensitive circuit generates an error signal when there is a difference between the two signal patterns. A method of inspecting the print quality of a matrix or inkjet printer. 2. The photosensitive device according to claim 1 preferably uses a matrix or a liquid die. In a device that inspects the printing quality of a printer, the photosensitive device of the device is a predetermined symbol printed by the printer in an area defined in relation to the print line; is placed in such a way that it passes under the photosensitive device, and in this way an electrical signal is generated. , its amplitude depends on the color contrast of the characters to the printed material, and this signal and a given A comparison is made between the signal patterns and the pattern generated by the photosensitive device and the predetermined signal. A photosensitive device containing a comparison circuit that generates a signal in response to differences between patterns A device that inspects the printing quality of paper or liquid jet writers. 3. In the device according to claim 2, the printed characters are the same by all printing elements. Inspect the print quality when forming dot rows and striking in the direction of paper feed. device to do. 4. In the apparatus of claim 2, in alternating lines, the printed characters are odd numbered. The print quality derived from the print element and in other rows from the even numbered print elements is checked. equipment to be inspected. 5. The apparatus according to claim 2, in which the signal is emitted in response to a difference between two signal patterns. A device for inspecting printing quality whose generated signal controls an alarm circuit.