JP2737267B2 - Automatic paper thickness detection mechanism setting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to an automatic paper thickness detection mechanism for automatically setting a distance between a paper surface and a print head in a printing apparatus, wherein a detection position on the paper surface changes depending on the type of paper or the number of copy papers. In order to correct that the distance between the paper surface and the print head is not set to be constant, a paper thickness detecting means for sensing the contact with the paper surface is mounted on the front surface of the carrier holding the print head, and the carrier is mounted on the carrier. An automatic paper thickness detection mechanism for automatically setting the interval between the print head and the paper surface by moving the paper forward from the initial retreat position and retracting the paper surface by a predetermined amount from the position where the paper surface is detected by the paper thickness detection means. In the printing apparatus, a first switch means for instructing a change in the predetermined retreat amount of the carrier and a finger for increasing the predetermined retreat amount by a predetermined amount each time the switch is pressed. A second switch means for performing the operation, a third switch means for instructing to reduce the predetermined retreat amount by a predetermined amount each time the switch is pressed, and the second switch means in response to a pressing instruction of the first to third switch means. Retreat amount changing means for changing a predetermined retreat amount, when automatically setting the interval between the print head and the paper surface, after pressing the first switch means,
The predetermined retreat amount is increased or decreased by a necessary amount by pressing the second switch means or the third switch means a required number of times.

[Industrial applications]

The present invention relates to automatic setting of an interval between a paper surface and a print head in a printing apparatus.

In a printing apparatus using an electromagnetic (wire dot) printhead, the distance from the surface of the paper to the surface of the printhead has a significant effect on print quality. Therefore, an automatic paper thickness detection mechanism that automatically detects the paper surface and automatically sets the distance from the paper surface to the surface of the print head to be constant has been put to practical use.

However, there is a problem that the detection position of the paper changes due to the difference in the type of paper and the number of copy papers, and a countermeasure is required.

[Conventional technology]

In a printing apparatus using an electromagnetic print head, the distance from the surface of the paper to the surface of the print head greatly affects print quality.

Conventionally, an operator generally adjusts the interval between the print head and the paper surface by setting a lever according to the thickness of the printing paper to be used.

Recently, printing with an "auto paper thickness detection mechanism" that automatically detects the paper surface and automatically sets the distance from the paper surface to the print head surface (this is called the head gap) is automatically set to be constant. The device has been put to practical use.

FIG. 5 is a diagram showing a main configuration of a printer including an automatic paper thickness detection mechanism.

 FIG. 5A is a top view of the whole.

FIG. 2B is a view as viewed from an arrow G (shown in FIG. 1A) and mainly shows a stepping motor and a gear.

FIG. 2C is a cross-sectional view as viewed from H (shown in FIG. 1A), and shows a print head, a carrier, and a platen.

Reference numeral 1 denotes an electromagnetic print head, which is held by a carrier 2. A paper thickness detection switch 21 is provided on the front of the carrier 2.
The switch is turned on when it comes into contact with the surface of the paper set on the platen 3.

The carrier 2 is held on an eccentric shaft 6 and slides, and the eccentric shaft 6 is rotated by the stepping motor 4 via gears 51, 52 and 53. In the eccentric shaft 6, the center of the gear 52 and the center of the shaft are deviated, and when the gear 53 rotates, the shaft moves forward and backward. Therefore, by rotating the stepping motor 4, the carrier 2 can be moved forward or backward with respect to the platen 3.

As shown in FIG. 5 (b), the gear 53 has a notch to form a cam, and the cam stopper turns on the initial position detection switch 54, so that the initial position (the print head carrier 2 is moved most backward). Position) can be detected.

FIG. 6 is a flowchart showing the operation of the automatic paper thickness detection mechanism.

FIG. 7 is a time chart showing the operation of the automatic paper thickness detection mechanism.

Hereinafter, the operation will be described with reference to FIGS. 5 and 7 in accordance with the processing steps of the flowchart of FIG.

The printer has been turned on.

In order to move the print head carrier 2 in the escape direction (the direction of retreating from the platen), a drive pulse is applied to a stepping motor to rotate the eccentric shaft.

When the initial position detection switch 54 is turned on, the initial position is detected.

The stepping motor 4 is stopped.

Receive a print command.

Check that the paper is loaded.

Move the print head carrier 3 in the approach direction (forward direction).
The eccentric shaft is rotated by the stepping motor 4 to move the eccentric shaft.

When the paper thickness detection switch 21 is turned on, the paper surface position is detected.

In order to move the print head carrier 3 by a predetermined amount in the escape direction, the stepping motor 4 is rotated by a step. (The number of steps a is the number of steps of the stepping motor 4 necessary to move a predetermined amount to obtain a predetermined optimum head gap.) By the processing steps, the head gap setting is completed, and printing is started.

[Problems to be solved by the invention]

As described above, by using the automatic paper thickness detection mechanism, even when using papers having different paper thicknesses, the paper thickness detection switch detects the paper position, and the print head is retracted by a predetermined amount from the detection position. This means that a certain head gap has been secured.

However, the paper detection position changes as shown in FIG. 8 due to the "strength" of the paper and the difference in the number of copy papers, and the distance from the paper surface to the print head surface is not always constant. There is a problem.

The problem to be solved by the present invention is to solve such a conventional problem and to provide a setting method for controlling the distance from the paper surface to the print head surface to a constant value regardless of the type of paper set. It is in.

[Means for solving the problem]

FIG. 1 is a block diagram showing the configuration and principle of the present invention.

 In the figure, reference numeral 1 denotes a print head.

 Reference numeral 2 denotes a carrier that holds a print head.

Reference numeral 21 denotes a sheet thickness detecting means (21) which is attached to the front surface of the carrier 2 and detects contact with the sheet surface.

Reference numeral 71 denotes first switch means for instructing a change of the predetermined retreat amount of the carrier 2.

Reference numeral 72 denotes second switch means for instructing to increase the predetermined retreat amount of the carrier 2 by a predetermined amount each time the switch is pressed.

Reference numeral 73 denotes a third switch means for instructing to reduce the predetermined retreat amount of the carrier 2 by a predetermined amount each time the switch is pressed.

Reference numeral 81 denotes a retreat amount changing means for changing a predetermined retreat amount in response to a pressing instruction of the first to third switch means 71, 72, 73.

(Operation)

In the present invention, if the type of paper to be used or the number of copy papers is changed and the paper detection position is expected to change, or if the result of actual printing is too dark or too light,
At the time of setting the space between the paper surface and the print head surface (head gap), after the first switch 71 is pressed, the second or third switch 72, 73 is pressed a number of times determined according to the state.

The retreat amount changing means 81 includes the first to third switch means 7.
Based on the depression of 1, 72, 73, the predetermined retreat amount a held by the automatic paper thickness detecting mechanism is increased or decreased, and the head gap is automatically set by retreating by the changed retreat amount.

The first to third switch means 71, 72, 73 may be of any type, but the example shown in FIG. 1 is based on a combination of a plurality of switches so as not to increase the number of switches on the operation panel. This shows an instruction indicated by the switch.

That is, the four buttons are simultaneously pressed to serve as the first switch means 71, and the subsequent top button is pressed to serve as the second switch means 72, and the second button from the top is pressed. Third switch means
It plays 73 roles.

As a result, the head gap can be corrected to a fixed value (a state in which the print quality is good and the slack of the ribbon and the stain are not generated).

〔Example〕

FIG. 2 is a diagram showing switches on an operation panel according to one embodiment of the present invention.

The operation panel of the printing apparatus according to the present embodiment has four switches A, B, C, and D. Each of the four switches is used to switch between online / offline, page break, line feed, and switch status mode display. Along with the function, another function is provided by pressing a combination of a plurality of switches.

For example, as shown in the figure, by simultaneously pressing the four switches A, B, C, and D, the “setup mode” is designated, and subsequently, by simultaneously pressing the three switches A, B, and C, the “backward mode” is displayed. "Change of quantity a" is selected.

In this state, when the A switch is pressed, the predetermined retreat amount a is changed by one step each time the switch is pressed (one step of the stepping motor for moving the print head carrier forward / backward, and in this embodiment, one step of the print head carrier). ,
Show an instruction to increase by 0.003mm).

When the B switch is pressed, a is set to 1 each time the switch is pressed.
Give an instruction to decrease the step.

FIG. 3 is a flowchart showing a setting operation according to an embodiment of the present invention.

As shown in the figure, when the setup mode of the printing apparatus is designated, the item "change of the retreat amount a" is selected by the combination switch as described above, and the retreat amount a is changed by pressing a predetermined switch. And make settings.

The monitoring of the pressing of these switches and the control corresponding to the pressing, the control of the sheet thickness detecting mechanism, and the control of the retraction amount are performed by a program held by a microprocessor in the printing apparatus.

By pressing switches A, B, C, and D simultaneously, the setup mode is designated.

"Change of retreat amount a" by pressing switches A, B and C simultaneously
Select the item of.

If the print result is too light, press the A switch.

Each time the switch is pressed, the retreat amount a is increased by one step.

If the print result is too dark, press the B switch.

Each time the switch is pressed, the retreat amount a is reduced by one step.

The setting of the head gap ends with the changed retreat amount.

Printing starts.

FIG. 4 is a diagram showing an operation panel according to another embodiment of the present invention.

In this embodiment, a button 74 as shown in FIG.
Is provided, and after a predetermined head gap setting operation, the operator determines the print quality and performs the following operation so that the head gap can be finely adjusted.

"Light print" ... Press the upper part of button 74.

Press the print head toward the platen one step / press (0.00
3mm).

"Ribbon stains come out" ... Press the lower part of button 74.

Press the print head one step / press from the platen side (0.00
3mm).

〔The invention's effect〕

As is apparent from the above description, according to the present invention, there is a remarkable effect that it is possible to set so as to obtain good print quality regardless of the type of paper and the setting method.

[Brief description of the drawings]

1 is a diagram showing the configuration and principle of the present invention, FIG. 2 is a diagram showing switches on an operation panel in one embodiment of the present invention, FIG. 3 is a flowchart showing a setting operation according to one embodiment of the present invention, FIG. 4 is a view showing an operation panel of another embodiment of the present invention, FIG. 5 is a view showing a main part of a printer having an automatic paper thickness detecting mechanism, and FIG. 6 is an operation of the automatic paper thickness detecting mechanism. FIG. 7 is a time chart showing the operation of the automatic paper thickness detection mechanism, and FIG. 8 is a diagram showing a change in the paper detection position. In the figure, 1 is a print head, 2 is a carrier, 3 is a platen, 4 is a stepping motor, 6 is an eccentric shaft, 21 is a paper thickness detection switch (means), 51, 52, and 53 are gears, and 54 is an initial position detection switch. Reference numerals 71, 72, and 73 denote switch means, 74 denotes a button, and 81 denotes retreat amount changing means.

Claims (1)

(57) [Claims] 1. A paper thickness detecting means (21) for detecting contact with the paper surface is mounted on the front surface of a carrier (2) holding a print head (1), and the carrier (2) is advanced from an initial retracted position. An automatic paper thickness detection mechanism for automatically setting the interval between the print head (1) and the paper surface by retracting the paper surface by a predetermined amount from the position where the paper surface is detected by the paper thickness detection means (21). In the printing apparatus, a first switch means (71) for instructing a change of the predetermined retreat amount of the carrier (2) and a second switch means for instructing to increase the predetermined retreat amount by a single press. A switch means (72); a third switch means (73) for instructing to reduce the predetermined retreat amount by a predetermined amount each time the switch is pressed; and a first to a third switch means (71), ( 72), (7
3) a retreat amount changing means (81) for changing the predetermined retreat amount in response to the pressing instruction of 3), wherein when the interval between the print head (1) and the paper surface is automatically set,
After the first switch means (71) is pressed, the second switch means (72) or the third switch means (73) is pressed a required number of times to increase or decrease the predetermined retreat amount by a necessary amount. A setting method of an automatic paper thickness detection mechanism, characterized in that the control is performed so as to cause the automatic paper thickness detection mechanism to perform the setting.