JPH03213296A - Cutter position measuring method - Google Patents

Abstract

PURPOSE:To measure a relative position of a cutter with a recording head without entailing any artificial errors by feeding a sheet of recording paper backward after cutting it with a cutter, and counting the number of position measuring marks on the recording paper detected by a sensor installed in space between the cutter and the recording head. CONSTITUTION:Supposing that there is a positional error in a cutter 8, a cut end comes off a measuring mark at the center in the same direction as far as a quantity conformed to size of the error and its direction, whereby the number of position measuring marks being determined by a position of the cutter 8 or the positional error are left behind short of the cut end of recording paper 1. consequently, the recording paper 1 is fed reversely, and the position measuring marks left behind in a spot short of the cut end of the recording paper 1 are detected by CCD sensors 6, 7, while the number of these marks is counted by a counting part 11, through which a relative cutter position to a recording head 4 is measured.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for measuring the position of a cutter for cutting recording paper in an image recording apparatus such as an electrostatic plotter.

2. Description of the Related Art A method for measuring cutter position in a conventional electrostatic plotter will be explained with reference to FIGS. 1 and 3.

In FIG. 1, ■ is electrostatic recording paper, 2 and 3 are rollers for conveying the recording paper 1 driven by a step motor (not shown), etc., and 4 is electrostatic recording that forms an electrostatic latent image on the recording paper 1. The head, 5 is a developer for developing the electrostatic latent image, and 6 and 7 are CCD sensors for reading the recorded state υ. In the case of overlapping recording, a reference mark recorded on the recording paper 1 is read by the CCD sensor 6.7, and the recording position of the image is corrected using the reference mark as a positional reference. 8 is a cutter for cutting the recording paper 1.

This cutter 8 is arranged so that the recording paper conveyance distance from the electrostatic recording head 4, that is, the relative position with respect to the electrostatic recording head 4 is a designed value t. Since there is a positional error, and a positional error also occurs when the cutter 8 is replaced, the actual position of the canter 8, that is, L, is measured for each individual device.
It is necessary to adjust the recording paper feed amount or cutter position according to the measurement results.

Conventionally, an electrostatic recording head 4 prints a canter on the recording paper 1.
After recording the position measurement line parallel to the cutting surface of 8,
The recording paper 1 is sequentially fed by an amount equal to the design value t and cut by the cutter 8, and the deviation Δt between the cut end of the recording paper 1 and the position measurement line is manually measured, and L= is calculated as ΔL. was.

FIG. 3 is an explanatory diagram of this measurement, and shows the case where L>t. 1A is the cut end of the recording paper 1, and 9 is a line for position measurement.

Problems to be Solved by the Invention However, the above-mentioned method that relies on manual labor has problems in terms of measurement efficiency and accuracy, and it is difficult to automatically adjust the recording paper feed amount according to the measurement results. The problem was that it was impossible.

One way to solve this problem is to newly install a sensor at the position of the cutter 8, record a position measurement line with the electrostatic recording head 4, and then press the recording paper 1 until the line is detected by the sensor. A conceivable method is to calculate υ by sequentially feeding the recording paper and converting the number of drive pulses of a conveyance drive pulse motor into a distance by, for example, counting the number of drive pulses of a conveyance drive pulse motor. However, it is necessary to add a sensor dedicated to measurement (change the device configuration),
Furthermore, in order to obtain the required measurement accuracy, a highly accurate and expensive sensor must be used and positioning must be performed with high precision, which is not necessarily a preferable method.

The present invention has been made in view of the above-mentioned problems, and does not require the addition of expensive high-precision sensors that would increase costs.
It is an object of the present invention to provide a cutter position measuring method that can eliminate human errors and inefficiencies, and also facilitates automatic adjustment of the recording paper feeding amount according to measurement results.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a recording head for image recording to line up a predetermined number of position measurement marks such as lines on recording paper at regular intervals in the conveying direction of the recording paper. After recording, the recording paper is sequentially fed by a predetermined amount corresponding to the designed relative position of a cutter for cutting the recording paper with respect to the recording head and cut by the cutter, and then the recording paper is fed backwards. The relative position of the cutter to the recording head is measured by counting the number of position measurement marks on the recording paper detected by a sensor provided between the cutter and the recording head.

For example, position measurement marks are recorded at regular intervals at the center of the recording head and in front and behind it, and the recording paper is sequentially fed by an amount equal to the designed recording paper transport distance from the recording head to the cutter and cut by the cutter. . If the position of the cutter accurately matches the designed position, the center position measurement mark and the cut edge of the cutter should match. If there is a position error of the cutter, the cut end will be shifted from the center measurement mark in the same direction by an amount corresponding to the size and direction of the error, and the cut end will be shifted from the center measurement mark to a number of positions determined by the cutter position or position error. A measurement mark remains in front of the cut edge of the recording paper.

Therefore, the position of the cutter relative to the recording head can be measured by reversing the recording paper, using a sensor to detect the position measurement marks left in front of the cut edge of the recording paper, and counting the number of marks. can.

Further, the position measurement accuracy is determined by the interval between the position measurement marks, and for example, if the position measurement marks are recorded at intervals corresponding to the minimum feed amount of the recording paper, the necessary and sufficient measurement accuracy can be obtained.

Furthermore, as a sensor for reading position measurement marks, it is possible to use a CCD sensor, etc., which is provided for reading reference marks in the case of overlapping recording, so there is no need to add an expensive high-precision sensor separately. There is no.

EXAMPLE An example of the present invention applied to an electrostatic printer will be described with reference to FIGS. 1 and 2. FIG.

In FIG. 1, reference numeral 11 denotes a counting section for counting the number of position measurement marks detected by the CCD sensor 6.7 when the recording paper 1 is fed backward. This counting unit 11 is a counter that is originally included in the electrostatic plotter, or a C
This can be easily realized using the functions of the PU. In addition, if the recording paper feeding amount is automatically adjusted according to the measurement results, it is necessary to place the counting section 11 inside the electrostatic plotter, but if not, the counting section 11 may be installed outside the electrostatic plotter. You can also do it.

Next, the cutter position measuring operation will be explained with reference to FIG.

In the case of cutter position measurement, first a predetermined number of position measurement marks are recorded on the recording paper 1 as an electrostatic latent image by the electrostatic recording head 4, and then developed by the developer 5. Then, the center position measurement mark is located at the center of the electrostatic recording head 4 (
Position the recording paper 1 so that it matches the position reference (position reference).

The prisoner in Figure 2 shows this state. 12 is a line as a mark for position measurement. In this example, a total of seven lines 12 are recorded, including one line that coincides with the center position 13 of the electrostatic recording head 4 and three lines before and after it. Further, the interval between the lines 12 is, for example, the minimum feed amount α of the recording paper 1.

If the recording paper transport driving motor is a pulse motor, α is determined by the rotation angle of the pulse motor per pulse, the diameters of the rollers 2 and 3, and the like.

Next, the recording paper 1 is progressively fed by an amount equal to the designed recording paper transport distance B from the center of the electrostatic recording head 4 to the center of the cut surface of the cutter 8, and the cutter 8 moves the recording paper 1
to be severed.

(J3) in FIG. 2 shows the cutting state. Cutter 8
If it is in the designed position, the center line 12° and the cutting position 14 should coincide. However, in this example, since the positional relationship is as shown, L=l+ΔL, and it is clear that Δt−α+Δα is the positional error of the cutter 8. And Δα is at most 1 recording paper
Since it is only the minimum feed amount of , and there is no problem even if this is ignored, the accuracy is sufficient even if it is assumed that L=t+α. As is clear from this equation, the position of the cutter 8 can be determined by the number of lines 12 on this side of the cutting position 14.

Therefore, the recording paper 1 was fed backwards, and the CCD sensor 6.7
By counting the number of lines 12 detected until the cut end of the recording paper 1 passes by using the counting section 11,
The actual cutter position can be measured with high precision.This measurement result is then sent to the electrostatic plotter control unit (CPU).
), it is possible to automatically adjust the feed amount, etc. for ejecting the recording paper.

Note that the center line 12o does not necessarily have to coincide with the center position 13 of the electrostatic recording head 4 at the start of sequential feeding of the recording paper l. The point is that if the relative position between the line 12 and the center of the electrostatic recording head 4 is specified at the start of progressive feeding,
A similar measurement is possible by correcting the progressive feed amount according to the position.

Although this embodiment is an example of an electrostatic plotter, the present invention is similarly applicable to image recording apparatuses using different recording methods. Furthermore, any appropriate symbol other than a line may be used as the position measurement mark.

Effects of the Invention As is clear from the above description, the present invention records a predetermined number of position measurement marks, such as lines, on a recording paper by arranging them at regular intervals using a recording head, and then cutting the recording paper. The recording paper is fed forward by a predetermined amount corresponding to the designed relative position of the cutter with respect to the recording head, and is cut by the cutter, and then the recording paper is fed backwards to cut the recording paper between the cutter and the recording head. By counting the number of position measurement marks on the recording paper detected by the sensor,
Since the position of the cutter relative to the recording head is measured, it is possible to measure the cutter position with high precision and efficiency by eliminating human errors and inefficiencies, and also eliminates the possibility of high This has the advantage that there is no need to add a precision sensor, and furthermore, it is possible to easily automatically adjust the amount of recording paper feed according to the measurement results.

4,

[Brief explanation of drawings]

FIG. 1 shows an electrostatic plotter according to an embodiment of the present invention: recording paper, 4: electrostatic recording head, 5: developer, 6.
7... CCD sensor, 8... Cutter, 11...
Counting part, 12 (12o=...912g)...Position measurement line (mark), 13...Center position of electrostatic recording head, 14...Cutting position.

Claims (1)

[Claims] A recording head for recording an image records a predetermined number of marks such as lines on a recording paper at regular intervals in the conveyance direction, and then a cutter for cutting the recording paper is designed for the recording head. The recording paper is forwardly fed by a predetermined amount corresponding to the relative position of the recording paper and cut by the cutter, and then the recording paper is fed backward and detected by a sensor provided between the cutter and the recording head. A method for measuring a cutter position in an image recording apparatus, comprising counting the number of marks.