JPS5952132B2 - Paper feed control circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a paper feed control section of an optical character reader (hereinafter abbreviated as OCR) among input devices for an electronic computer.

[Background of the invention]

The paper feed control unit of OCR can be broadly classified into two types: a system that reads the form by temporarily stopping the document in the reading unit, and a system that reads the form while it is running.The former is usually a page reader type, and the latter is a document reader type. It corresponds to the type.

In order to standardize the paper feed control for both types of OCR,
Problems arise in detecting abnormalities, particularly in the jam detection method for detecting when a form jams on the travel path, making it impossible for that form and subsequent forms to travel. In the normal document reader type jam detection method, the time required from the leading edge of one form to pass the detector to the leading edge of the next form to pass the detector is checked, and even if a predetermined period of time has elapsed, There is a method for detecting a jam if the paper does not pass through.
However, this method cannot be directly applied to page reader types where forms are temporarily stopped. [Object of the Invention] An object of the present invention is to provide a paper feed control circuit that can detect jams in both document reader types in which a form is read while it is running, and page reader types in which a form is read in a paused state. It's about doing.

[Summary of the invention]

In the present invention, the detector on the road is used to check the time from when a certain form passes until the next form arrives, so that it can be applied to a page reader type. , is characterized in that the above-mentioned time check is omitted while the form is temporarily stopped.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG.

FIG. 1 is a block diagram of a jam detection circuit. The running signal 11 is a control signal for running the form on the running road, and is output from a control unit such as a microprocessor (not shown). For example, when the logic level is ``1'', the motor is driven to convey the form, and when the logic level is ``0'', the motor is stopped. This running signal 11 is input to an AND circuit j7.
The other input to the AND circuit 7 is the clock pulse 12, which is output from a control section (not shown). Therefore, when the running signal 11 is '1', the clock pulse 12 is output from the AND circuit 7. The output of the AND circuit 7 becomes the count up signal 1 of the counter 4. This is a signal indicating the presence or absence of a form, and the signal is a1 when a form is detected, and a0 when no form is detected.The detector is composed of, for example, a light emitting element and a light receiving element.When the detector output 13 is ゜"1" When the one-shot circuit 2 operates, its output 3 clears the counter 4. Therefore, the output of the counter 4 is the time from when a certain form reaches the detector until when the next form arrives. Moreover, the page reader
When reading by type, the count value of the counter 4 is not updated because the running signal 11 is "0" while the form is temporarily stopped for reading.On the other hand, the count value of the counter 4 is not updated as the time for jam detection. The specified time value 14 is set in the register 5 in advance, and this is compared with the output of the counter 4 by the comparator 6, and when the latter exceeds the former, a jam detection signal is output.The above content can be further simplified. This can be achieved as shown in FIG.

The count down signal 21 of the counter 25 is obtained by calculating the AND of the tally pulse 12 and the running signal 11 indicating the running state of the form in an AND circuit 22.
When the countdown signal 21 is "1", the tally pulse 512 is outputted as the countdown signal 21. When the bill reaches a detector on the road, the one shot circuit 23 is activated by the detector output 13, and a counter load signal 24 is generated. 24, a preset time designation value 14 for jam detection is loaded and set in the counter 25.The counter 25 counts down every time the clock pulse 12 is input after the form reaches the detector. A jam detection signal is output when the count value reaches zero before the next form reaches the same detector. [Effects of the Invention] The present invention makes it possible to detect jams common to document reader types and page reader types. A paper feed control circuit with a detection function can be realized at low cost.

Furthermore, if the same device is to have the functions of a document reader and a page reader, the switching can be done easily without any changes.

[Brief explanation of drawings]

FIG. 1 is a plotter diagram showing one embodiment of the invention, and FIG. 2 is a plotter diagram showing another embodiment. 2...One shot circuit, 4...Counter, 5...Registor, 6...Comparator,
23... One shot circuit, 25...
counter.

Claims (1)

[Claims] 1. A circuit that outputs a clock pulse when a form is in a running state, a detector that detects the presence or absence of a form on the road, and a preset time value set when the detector detects the leading edge of the form, and A paper feed control circuit comprising: a counter that performs subtraction every time a clock pulse is input; and a paper jam is detected when the value of the counter reaches zero before the next document is detected by the detector.