JPH0481512B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing device using a removable printing wheel, and more particularly to a printing wheel presence/absence detection device for a printing device that detects whether or not a printing wheel is attached.

[Prior Art] Some printing devices include a carriage whose movement is controlled along a platen on which printing paper is set.
Printing consisting of a printing wheel with spokes with type at the tip formed around the entire circumference, a printing wheel motor consisting of a stepping motor, a printing hammer driven by a hammer magnet, a printing ribbon, a printing ribbon motor, etc. Equipped with a mechanism, when a character code is input from the outside, the carriage is moved to the printing position on the printing paper set on the platen, and the printing wheel motor prints so that the characters corresponding to this character code face the above printing position. Some types print out characters corresponding to character codes onto printing paper by rotating a wheel and then striking the type with a printing hammer.

In general, in such printing devices, cleaning is performed to clean the ink from the printing ribbon adhering to the type, to clean the above-mentioned components mounted on the carriage, or to change the type or shape of the type. Since it is necessary to replace the printing wheel itself with another type of printing wheel, the structure is such that the printing wheel can be easily installed and removed by the user.

[Problems to be Solved by the Invention] However, the printing device in which the printing wheel can be easily attached and detached as described above has the following problems. In other words, in such a printing device, each character code stored in an internal storage unit such as ROM, and the corresponding printed character indicated by the number of rotation pitches of the printing wheel motor from the home position (reference angular position) of the printing wheel. When the power is turned on, the printing wheel is rotated so that the home position is located at a predetermined specific position, such as the printing position, in order to correspond to the rotational angle position of the spoke formed. I have to. Then, as a means for detecting that the home position has reached a specific position, a home position detection hole is bored in the home position of the printing wheel, and this home position detection hole is arranged at the above specific position. It was detected by a photo sensor.

However, since the photo sensor detects light unconditionally if, for example, the print wheel is not attached, it is determined that the print wheel is properly attached and the home position has been detected. Therefore, even if the printing wheel is not attached, there is a risk that the printing operation may be started in response to a command from an external host computer, for example.

The present invention has been made based on these circumstances, and its purpose is to detect whether or not a printing wheel is installed at the time of starting operation of a printing device without adding an additional mechanical detection device. An object of the present invention is to provide a device for detecting the presence or absence of a printing wheel of a printing device, which detects the presence of a printing wheel in a printing device, and issues a warning if the printing wheel is not installed, thereby preventing malfunctions of the printing device.

[Means for Solving the Problems] The printing wheel presence/absence detection device for a printing device of the present invention is a printing device using a printing wheel that is detachably attached to a gear rotated by a printing wheel motor. When detecting the home position detection hole and the auxiliary detection hole by providing multiple auxiliary detection holes at multiple positions on the circumference of the gear with the same radius as the radius of the position where the home position detection hole is drilled in the printing wheel. A photo sensor that outputs a hole detection signal is installed between the print wheel and gear at the same time, and a pitch number counter and photo sensor that measure the number of rotation pitches of the print wheel motor corresponding to the spoke rotation pitch of the print wheel are output. Two counters are provided, including a detection hole number counter that measures the number of hole detection signals, and the detection hole number counter detects multiple detection holes before the pitch number counter measures a predetermined allowable number of pitches that is less than the number of installed spokes. It is designed to output a print wheel no-installation signal when the measurement is taken.

In addition to the above invention, in another invention, a printing wheel support is provided for pressing the printing wheel against the gear, and one of the light emitting part and the light receiving part constituting the photo sensor is attached to the printing wheel support, and the other one is attached to the printing wheel support. is attached to a fixed part via a printing wheel and a gear. When the detection hole number counter measures a plurality of detection holes before the pitch number counter measures a predetermined first allowable number of pitches that is less than or equal to the number of installed spokes, and when the detection hole number counter measures the number of detection holes. When the pitch number counter measures a predetermined second allowable number of pitches that exceeds the number of installed spokes, a print wheel non-installation signal is output.

[Function] With the printing wheel presence/absence detection device of the printing device configured as described above, the printing wheel has one point on the circumference.
Home position detection holes are drilled at certain locations, and auxiliary detection holes are drilled at multiple locations around the gear. Therefore, if the print wheel is not installed and the print wheel motor is rotated, the photo sensor will always penetrate the gear until the pitch number counter measures the number of pitches corresponding to one rotation of the print wheel. A plurality of auxiliary detection holes provided are detected. As a result, a print wheel non-installation signal indicating that the print wheel is not installed is output.

In another invention, in addition to the above-mentioned effect, since the printing wheel is pressed against the gear by the printing wheel support, a photo sensor is formed when the printing wheel support is shifted from the gear and the printing wheel is removed. The light emitting part and the light receiving part are separated from each other. Therefore, in this state, even if the print wheel motor is rotated more than the number of pitches corresponding to one rotation of the print wheel, no hole detection signal will be output from the photo sensor. Therefore, if the pitch number counter exceeds one rotation, the second
When the allowable number of pitches is measured, a print wheel no-installation signal is output.

[Example] An example of the present invention will be described below with reference to the drawings.

1 and 2 are schematic cross-sectional views showing the main parts of the printing wheel presence/absence detection device of the printing device according to the embodiment, and FIG. The figure shows a state in which the print wheel support is tilted and the print wheel is removed.

In the figure, reference numeral 1 denotes a platen (not shown) on which printing paper is set, and a printing mechanism 2 is mounted on a carriage (not shown) whose movement is controlled along this platen 1. A printing wheel motor 4 composed of a stepping motor is fixed to the frame 3 of this printing mechanism 2, and a gear 6 connected to a rotating gear 5 attached to the shaft of this printing wheel motor 4 is connected to a rotating shaft. It is attached to the frame 3 via 7. The printing wheel 8 is connected to the free end of the rotating shaft 7 of this gear 6 by the spring 1 of the printing wheel support 9.
It is pressed by the shaft rod 11 which is biased at zero. The other end (not shown) of the printing wheel support 9 is pivotally supported by the frame 3 of the printing mechanism 2, and when the lever 12 is pulled backward, the shaft 11 is moved from the rotation shaft 7 of the gear 6 as shown in FIG. away from the free end. At the same time, the axis 7 of the gear 6 and the axis of the shaft 11 of the print wheel support 9 are misaligned.

This printing wheel support 9 has a printing wheel 8
A light emitting element 14 of a photo sensor is installed at a position opposite to a home position detection hole 13 bored at the home position of the light emitting element 1.
A light receiving element 15 that receives light from the frame 3 is attached to the frame 3.

The printing mechanism 2 also includes a printing hammer 18 for hitting the type 17 formed at the tip of each spoke 16 of the printing wheel 8, and a hammer solenoid 19 for driving the printing hammer 18.
is provided.

As shown in FIG. 3, the printing wheel 8 has a plurality of spokes 16 having typefaces 17 at their tips formed around the entire circumference of a circular rotating base plate 20 at constant pitch intervals. The home position detection hole 13 is installed in the rotating board 20 near the spokes 16a of the designated specific type 17a.
is drilled. Further, a through hole 21 is provided in the center of the rotating board 20, with which the free end of the rotating shaft 7 of the gear 6 and the shaft 11 of the print wheel support 9 come into contact.

On the other hand, the gear 6 is provided with a plurality of auxiliary detection holes 22 on its circumference, as shown in FIG. The radius of the position where this auxiliary detection hole 22 is provided is the same as the radius of the home position detection hole 13 of the print wheel 8. The intervals between the auxiliary detection holes 22 are set to the angle required for each spoke 16 of the printing wheel 8 shown in FIG. 3 to move four pitches. That is, when the print wheel 8 rotates by four characters,
The next auxiliary detection hole 22 is detected in the gear 6.

FIG. 5 is a block diagram showing a schematic configuration of a printing device incorporating the printing wheel presence/absence detection device of the present invention, and 31 in the figure executes various information calculation processes based on character codes input from the outside and prints out. This is the CPU (central processing unit) that performs processing. This CPU1
3 is a ROM 33 that stores fixed data such as a control program and a spoke rotation position table of each type 17 corresponding to a character code through a bus line 32 consisting of a data bus and an address bus, and a ROM 33 that stores fixed data such as a spoke rotation position table of each type 17 corresponding to a control program and character code, and a rotation pitch of the spokes 16 of the print wheel 8. Pitch number counter RA1 and light emitting element 14 that measure the rotational pitch number PC of the corresponding printing wheel motor 4
and a detection hole number counter RA2 that measures the number of hole detection signals output from a photo sensor consisting of a light receiving element 15, that is, the number of detected holes HC, and a RAM 34 that temporarily stores variable data such as input character codes.
An input interface 3 that receives data such as character codes sent from the host computer 35
Control 6.

Furthermore, the bus line 32 of the CPU 31 includes a hammer solenoid output port 37 for outputting a drive signal to the hammer solenoid 19 that drives the printing hammer 18, a light emitting element 14 and a light receiving element 1.
a photo sensor input port 39 for inputting a hole detection signal from a photo sensor 38 consisting of a photo sensor 38, and a display section for lighting an indicator lamp 40 for displaying a warning when the print wheel 8 is not attached to the print mechanism 2 An output port 41, a motor output port 43 for sending a drive signal to a motor drive circuit 42 that drives each motor, and the like are connected.

When the light output from the light emitting element 14 is received by the light receiving element 15, the photo sensor 38 detects [H]
Outputs level hole detection signal.

The motor drive circuit 42 also includes a carriage motor 44 for moving the carriage on which the printing mechanism 2 is mounted, the printing wheel motor 4,
A paper feed motor 45 is connected to the paratenn 1 to feed the printing paper.

The CPU 31 is configured to execute a process of detecting whether the printing wheel 8 is properly mounted or not according to the flowchart of FIG. 6 when the printing apparatus is powered on. That is, when the power is turned on, each input/output port is initialized, and the RAM 34 is
Inside pitch number counter RA1, detection hole number counter
Executes initial processing such as clearing RA2, etc. When the initial processing is completed, the pitch number counter in RAM34
The value of the pitch number PC of RA1 is set to [12], which is the first allowable number of pitches. 1 to the motor drive circuit 42 via the motor output port 43 at P1.
A pulse drive signal is sent to rotate the print wheel motor 4 by one pitch. Then, the rotary gear 5 shown in FIG. 1 and the gear 6 pivotally supported on the frame 3 by the rotary shaft 7 rotate by an amount corresponding to the rotation of the printing wheel 8 by one character pitch.

Next, the level of the signal input from the photo sensor 38 via the photo sensor input port 39 is checked. When the signal level is H level, the light emitting element 14
It is determined that the light outputted from the auxiliary detection hole 22 of the gear 6 has been input to the light receiving element 15, and the detection hole number HC of the detection hole number counter RA2 of the RAM 34 is increased by one. Then, the pitch number PC of the pitch number counter RA1 is decreased by one. Note that if the output signal of the photo sensor 38 is at L level, only the number of pitches PC is decreased without increasing the number of detection holes HC. When the pitch number PC has been subtracted from the pitch number counter RA1, it is confirmed that the pitch number PC has not reached 0, and then the process returns to P1 and the printing wheel motor 4 is further rotated by one pitch.
Then, the output signal level of the photo sensor 38 is checked again.

When the initially set rotation of the print wheel motor 4 for 12 pitches is completed in this way, the number of detection holes HC counted by the detection hole number counter RA2 while the print wheel motor 4 rotated for 12 pitches is determined at P2. Examine the value. And the number of detection holes HC is 2
When the printing wheel 8 becomes the rotation axis 7 of the gear 6,
It is determined that the print wheel is not installed between the shaft rod 11 of the print wheel support 9, and a print wheel non-installation signal is sent to the display unit output port 41, and the display lamp 4 is output.
0 lights up.

If the detection hole number HC of the detection hole number counter RA2 is less than 2, the print wheel 8 is moved as shown in FIG.
It is determined that the print wheel support 9 is either properly installed, or the print wheel support 9 has been left in an inclined state with the print wheel 8 removed, as shown in FIG. and,
The pitch number PC of the pitch number counter RA1 is set to [200], which is a second allowable pitch number larger than the total number of spokes 16 formed on the circumference of the printing wheel 8.

When the setting of the pitch number PC is completed, the printing wheel motor 4 is rotated by one pitch at P3. And the pitch number of pitch number counter RA1
After subtracting PC by 1, when it is confirmed that the pitch number PC after subtraction has not reached 0 and that the output signal of the photo sensor 38 is at the L level, the process returns to P3 and the printing wheel motor 4 is activated for one more pitch. Rotate.

Then, before the hole detection signal of H level is output from the photo sensor 38, the pitch number counter is
When the RA1 pitch number PC reaches 0, the light emitting element 14
Since the axes of the light receiving element 15 and the light receiving element 15 are misaligned, it is determined that the printing wheel 8 is not attached as shown in FIG. 2, and the display lamp 40 is turned on.

On the other hand, if the output signal of the photo sensor 38 becomes H level before the pitch number PC of the pitch number counter RA1 reaches 0, the photo sensor 38 has detected the home position detection hole 13 of the print wheel 8, so the print wheel 8 is As shown in FIG. 1, it is determined that the device is properly installed.

In the printing wheel presence/absence detecting device configured in this way, the printing wheel 8 is detected as shown in FIG.
Suppose that the printer was removed and the power was turned on by mistake while the print wheel support 9 was tilted. In this case, since the axes of the light emitting element 14 and the light receiving element 15 of the photo sensor 38 do not match, the photo sensor 38 outputs a hole detection signal even if the print wheel motor 4 is rotated by more than one revolution of the print wheel 8. Never. Therefore, it is detected that the print wheel 8 is not properly mounted, and the indicator lamp 40 lights up.

Further, when the print wheel support 9 is returned to its normal position without the print wheel 8 attached, the axes of the light emitting element 14 and the light receiving element 15 are aligned. However, since the print wheel 8 is not attached, the photo sensor 38 outputs a hole detection signal of H level every time the print wheel motor 4 rotates by four pitches. This means that two or more hole detection signals are output while the print wheel motor 4 rotates by a pitch, such as 12, which is smaller than the number of spokes installed for one rotation of the print wheel 8. Therefore, it is detected that the print wheel 8 is not properly installed, and the indicator lamp 40 lights up.As shown above, if the print wheel 8 is not properly installed, the internal control unit such as the CPU Error processing can be executed and erroneous printing operations can be prevented.

Furthermore, since the presence or absence of the print wheel is detected using the home position detection mechanism of the print wheel 8, there is no need to separately install a dedicated print wheel detection mechanism.

[Effects of the Invention] As explained above, according to the present invention, it is possible to detect whether or not a printing wheel is attached at the start of operation of the printing device, and to detect whether or not the printing wheel is attached, without adding an additional mechanical detection device. If this happens, a warning can be issued to that effect. As a result, malfunctions of the printing device can be prevented and reliability can be improved.

[Brief explanation of the drawing]

The figure shows a printing wheel presence/absence detection device of a printing device according to an embodiment of the present invention, and FIGS. 1 and 2 are cross-sectional schematic diagrams showing main parts of the same embodiment, and FIG. Partial view showing the print wheel,
FIG. 4 is a partial diagram showing the gears, FIG. 5 is a block diagram showing the printing device, and FIG. 6 is a flowchart showing the operation. 1... Platen, 2... Printing mechanism, 4... Printing wheel motor, 6... Gear, 7... Rotating shaft, 9
... Printing wheel support, 13 ... Home position detection hole, 14 ... Light emitting element, 15 ... Light receiving element, 16 ... Spoke, 17 ... Type, 18 ...
Printing hammer, 22... Auxiliary detection hole, 31...
CPU, 34...RAM, 38...Photo sensor,
40...Display lamp, RA1...Pitch number counter, RA2...Detection hole number counter.

Claims (1)

[Scope of Claims] 1. A printing wheel that is detachably attached to a gear rotated by a printing wheel motor, and that has a plurality of spokes having printed characters at their tips formed over the entire circumference at constant pitch intervals. The home position of the upper one location is determined by detecting a home position detection hole drilled in this home position,
In a printing device that performs a printing operation by searching for a spoke position of a spoke having printed characters corresponding to an input character code based on a determined home position, the home position detection hole in the printing wheel is bored. a plurality of auxiliary detection holes provided at a plurality of positions on the circumference of the gear having the same radius as the radius of the position; a photo sensor that outputs a hole detection signal when an auxiliary detection hole is detected; a chip number counter that measures the number of rotation pitches of the print wheel motor corresponding to the spoke rotation pitch of the print wheel; and a hole detection output from the photo sensor. A detection hole number counter that measures the number of signals, and a print wheel presence or absence when the detection hole number counter measures a plurality of detection holes before the pitch number counter measures a predetermined allowable number of chips that is less than or equal to the number of installed spokes. 1. A printing wheel presence/absence detection device for a printing device, comprising means for outputting a mounting signal. 2. A home position located at one location on the circumference of the print wheel, which is detachably attached to the gear rotated by the print wheel motor, and has a plurality of spokes with printed characters at their tips formed at regular intervals over the entire circumference. by detecting the home position detection hole drilled at this home position,
In a printing device that performs a printing operation by searching the spoke position of a spoke having printed characters corresponding to an input character code based on a determined home position, the printing wheel support member that presses the printing wheel against the gear; , a plurality of auxiliary detection holes provided at a plurality of positions on the circumference of the gear having the same radius as the radius of the position where the home position detection hole is bored in the printing wheel, and a light emitting section and a light receiving section. One is attached to the printing wheel support, and the other is attached to a fixed part via the printing wheel and the gear, and outputs a hole detection signal when detecting the home position detection hole and the auxiliary detection hole. a photo sensor that measures the number of rotation chips of the print wheel motor corresponding to the spoke rotation pitch of the print wheel; a detection hole number counter that measures the number of hole detection signals output from the photo sensor; When the detection hole number counter measures a plurality of detection holes before the pitch number counter measures a predetermined first allowable number of pitches that is less than or equal to the number of installed spokes, and when the detection hole number counter measures the detection holes. A printing wheel of a printing device characterized in that the printing wheel of the printing device is further provided with means for outputting a printing wheel non-installation signal when the pitch number counter measures a predetermined second allowable number of chips that exceeds the number of installed spokes. Presence detection device.