JPS63257642A - Printing of daisy wheel printer - Google Patents

Abstract

PURPOSE:To enable suitable shadow printing to be executed, by a method wherein a carrier is fed with no load in two way printing, and printing is started again after returning the carrier in the reverse direction by a transfer correction. CONSTITUTION:Before shadow printing is carried out a carrier 6 is moved from an initial position A by a movement that is the sum of transfer a correction N1 and a normal movement N2. That is, it is carried by the transfer correction N1 in excess at a reverse point. This transfer correction N1 means a no-lead feed when printing is not carried out. Then, the carrier 6 is returned by the transfer correction N1 when carried with no load, and driven reversely. Therefore, the carrier 6 is carried by the correction transfer distance N1 in excess, and printing is started again after returning by the distance. By such carrying with no load of the carrier 6, normal shadow printing is executed on the initial character after reversal of the carrier 6.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a daisy-wheel printer capable of bidirectional printing, and more particularly to a printing method for shadow printing and the like.

BACKGROUND OF THE INVENTION Conventionally, there has been a so-called daisy-wheel printer that prints by selectively impacting concentrically arranged characters onto recording paper via an ink ribbon. During actual printing, this type of printer moves the print head and recording paper relatively, and prints by impacting characters on the recording paper via an ink ribbon.

However, because of the structure in which printing is performed by impacting a character, it is necessary to temporarily stop the movement of the print head and recording paper at the time of impact.

For this reason, the printing speed is slow.Therefore, in order to compensate for this slow printing speed to some extent, a bidirectional printing method is used in which the print head and the recording paper move in both directions for each line. is commonly used.

On the other hand, as special printing by the above-mentioned daisy-wheel printer, shadow printing can be easily performed due to its unique structure. Here, shadow printing is a printing method in which a character that is the same as a character that has already been printed is printed in an overlapping manner, shifted laterally by a minute distance from the original printing position. The shifting distance is approximately 1/120".

When such shadow printing is performed, the printed characters become thicker and three-dimensional.

Problems to be Solved by the Invention When performing shadow printing, the distance of the printing position to be shifted during double printing is as small as approximately 1/120'. Therefore, a means for moving the print head and the recording paper, that is, a moving means, is required to have high precision. However, when bidirectional printing is performed, a small time difference occurs between when the moving means is actuated and when the print head starts the reversing operation. This is due to play in mechanisms in the moving means and backlash of gears used in the moving means. For this reason, when attempting to shadow print the first character after movement and reversal, it is not possible to secure a printing misalignment distance as small as about 1/120'. Such a phenomenon is not limited to shadow printing, but may also appear as a clear shift when the first character after movement and reversal is a half-width character, for example. Therefore, especially when shadow printing is performed, bidirectional printing is not normally performed, and in this case there is a drawback that the printing speed is slow. Further, if shadow printing is forcibly performed in bidirectional printing, the proper displacement of the printing position required for shadow printing cannot be ensured, resulting in a disadvantage that the printing quality is degraded.

Means for Solving the Problems The present invention provides, when shadow printing is performed during bidirectional printing, when the moving direction of the carrier on which the print head is mounted is reversed, the carrier is moved in a small correction direction from the reversed position to the reverse direction. After the carrier is moved in the reverse direction by the corrected movement amount, printing is restarted.

At the moment when the moving direction of the carrier is reversed, there is a slight delay in the reversing operation of the carrier due to play in the mechanism for driving the carrier. However, due to the empty feed corresponding to the corrected movement amount, such a delay in operation occurs by the same length as a whole from the printing start position after the empty feed. However, even when the first character after the carrier movement is reversed is shadow printed, the minute printing position shift required for shadow printing is ensured.

Appropriate shadow printing can be performed.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 to 4. A platen 2 for conveying the recording paper 1 is rotatably provided in a casing (not shown), and a carrier shaft 3 and a guide shaft 4 are arranged parallel to the platen 2. A carrier 6 on which a daisy-wheel print head 5 is mounted is slidably attached to the carrier shaft 3 and the guide shaft 4. A tension belt 8 that is stretched around two pulleys 7 arranged near both ends of the platen 2 is fixed to the carrier 6 . The print head 5 is.

A character portion of a daisy wheel (not shown) is arranged to face the platen 2 at the printing position,
An ink ribbon 9 is provided between the print head 5 and the platen 2.

As a drive source for each of the mechanisms described above, a platen motor 2a (hereinafter referred to as PM) that drives the platen 2 is provided. Further, a carrier motor 6a (hereinafter referred to as CM) that drives one of the pulleys 7 to move the carrier 6 is provided. Furthermore, a head motor 5a (hereinafter referred to as HM) that drives the print head 5
is provided.

Next, the electrical connections of each part will be explained.

First, the PM 2 a, the CM6a and the HM
5a is connected to the outboard of CPU II via a latch circuit 1o. A DIP switch 12 is connected to this inboard of the CPUI 1.

A memory 13 is connected via an address bus and a data bus.

In such a configuration, the print head 5 prints predetermined items on the recording paper 1 based on print information in the memory 13.

The printing method at this time is bidirectional printing. That is, the carrier 6 moves in the row direction along the platen 2, and when the -share is printed, a line feed is performed by the rotation of the platen 2, and the carrier 6 moves in the opposite direction in the row direction. Bidirectional printing is performed repeatedly. Note that the carrier 6 is driven to 0M6a, and the platen 2 is driven to PM2a.

Thus, during printing, the type of printing is selected by the DIP switch 12. That is, normal printing, shadow printing, or bowl printing is selected. Shadow printing is as described above.

Bold printing is a printing method in which the same character is overprinted by shifting it by a minute amount. Bold printing is a printing method in which the same character is overprinted in the same area. Here, when performing shadow printing, as shown in Fig. 1, the carrier 6
The movement amount is changed to the corrected movement amount N1 added to the normal movement amount N2. The details of the conveyance operation of the carrier 6 during such shadow printing will be explained based on the flowchart of FIG. 4. First, the normal movement amount N2 is set as a carrier count. The carrier count refers to the number of starts of the carrier 6, which repeats starting and stopping every minus character. Next, by switching the dip switch 12, it can be seen whether shadow printing is selected. If shadow printing is selected, the normal movement amount N2
+Corrected movement amount N1 is set as a carrier count. If shadow printing is not selected, separate processing is performed. Then, the carrier 6 is conveyed by 0M6a for one character and then stopped, but a time wait is added for each - character. After a 6-time wait to absorb mechanical vibrations,
The carrier count is decremented by 1, and such conveyance of the carrier 6 is continued until the carrier count becomes O. In this way, the carrier 6 moves from the initial position WIA to the normal movement distance N
2 plus the corrected movement amount N4. In other words.

Inverted position 1i! ! At B, the carrier 6 has a corrected movement amount N
It takes an extra minute to be transported. This corrected movement amount N2 is an empty feed amount at which printing is not performed.

Next, the air-fed straddling carrier 6 by the corrected movement amount N is returned and driven in the opposite direction. That is, when the carrier count reaches O, the driving of the carrier 6 is temporarily stopped after a time wait, and the carrier count is set by N□. Then, this time, the carrier 6 is driven in a direction opposite to the transport direction of the carrier 6 described above. Similarly at this time,
After the carrier 6 is stopped, a time wait is entered and the carrier count is decremented by 1, which continues until the carrier count reaches O. Then, when the carrier count becomes 0, if there is no carrier stop signal after the time wait, the carrier count N2 is set again and the same routine is repeated.

Therefore, in the case of shadow printing, the carrier 6 is further conveyed by the corrected movement amount N8 and returned by that amount, and then printing is restarted. Due to such empty feeding of the carrier 6, printing is performed over one entire line while there is a time difference between when the carrier 6 is reversed and when the carrier 6 actually operates, that is, there is a delay in the operation of the carrier 6. Therefore, the influence of the delay in the operation of the carrier 6 is uniform over the entire line.

Therefore, a minute deviation of approximately 1/120' between the first printing position and the second printing position required for shadow printing is ensured, and normal shadow printing is performed for the first character after the carrier 6 is reversed. Ru.

Effects of the Invention The present invention, when shadow printing or the like is performed during bidirectional printing, when the moving direction of the carrier on which the print head is mounted is reversed, the carrier is air-fed by a minute correction movement amount in the opposite direction from the reversed position. Since printing is restarted after the carrier is returned to the reversal direction by the amount of empty feed, even if there is a time difference between when the carrier's drive source operates and when the carrier actually moves, the printing start position after reversing will be the same. from 1
Uniform movement of the carrier is maintained over the entire line, and even when shadow printing the first character after the carrier movement is reversed, the slight deviation of the printing position required for shadow printing is ensured, ensuring proper printing. It has effects such as shadow printing.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a movement locus of a printing position showing an embodiment of the present invention, and FIG. 2 is a plan view of a printing mechanism. FIG. 3 is a block diagram showing the electrical connections of various parts, and FIG. 4 is a flowchart showing the carrier conveyance operation during shadow printing. 5...Print head, 6...Carrier, B...Reversal position, N2...Correction movement amount

Claims (1)

[Claims] When performing shadow printing, etc. during bidirectional printing, when the moving direction of the carrier on which the print head is mounted is reversed, this carrier is moved by a small correction movement amount in the opposite direction from the inversion position, and the carrier is moved by the correction movement. A printing method of a daisy wheel printer, characterized in that printing is restarted after returning to the reverse direction by an amount