JP2003231332A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a printer of such a system as not having a page mode but printing print data being transferred from a host sequentially in which uneven print due to temporary print stop in the way of page print is prevented without increasing the constitutional scale of the printer. <P>SOLUTION: Print speed is decreased when the volume of not yet printed data being left in a buffer memory 12 under print waiting state is decreased. Alternatively, print start is delayed by a set time when print data in a print stop prohibiting section is printed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer of a sequential printing system, and more particularly to a technique effective in preventing uneven printing due to temporary stoppage of printing during page printing.

[0002]

2. Description of the Related Art A printer having a page mode uses a large-capacity page memory to store print data page by page, and prints the print data transferred from a host computer (hereinafter referred to as a host) for one page. To start. In this type of printer, even if the transfer of print data is delayed or temporarily interrupted, there is no stoppage of printing in the middle of printing a page, and thus uneven printing can be prevented within the page.

On the other hand, a small-scale printer, such as a POS terminal, does not use the page memory but employs a method of sequentially printing the print data transferred from the host line by line. This type of printer does not require a large-capacity page memory and can be constructed in a small scale. If the page memory is unnecessary, the memory load of the printer control system can be reduced, and the so-called throughput of data processing in the printer can be increased accordingly. Also, when print data is delivered from the host via a communication line, etc., the printer can start printing without waiting for the print data to be completed for one page, so the waiting time from data delivery to the start of printing There is also an advantage that can be shortened. If the printing starts early, the user can quickly confirm the response from the host by starting the printing.

[0004]

In the above-described printer of the sequential printing system, the data transfer from the host is not smoothly performed due to the communication state, or the print data processing on the printer side is delayed due to complicated character decoration. In some cases, the printing operation may be temporarily stopped until the data (line data) necessary for printing is prepared. If the print stop occurs during page printing, the print pitch (line interval) is disturbed before and after the stop, and the print density is slightly changed, resulting in print unevenness in the page. In order to prevent the print unevenness, the page mode function described above may be provided, but this requires a large-capacity page memory, resulting in a large-scale printer configuration and a printer control system. There is a problem that the memory load becomes heavy, the throughput is lowered, and the waiting time from the data distribution to the start of printing becomes long.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a temporary printing method in the middle of page printing without increasing the configuration scale in a sequential printing type printer having no page mode. Another object is to effectively prevent uneven printing due to the temporary stop of printing.

[0006]

According to a first means of the present invention, in a printer of a system which does not have a page mode and sequentially prints print data transferred from a host,
A buffer memory that temporarily stores the data that is transferred from the host and is printed, and a print speed that slows the print speed when the amount of unprinted data remaining in the print wait state in this buffer memory decreases. A control means is provided. As a result, it is possible to effectively prevent print unevenness due to a temporary print stop during page printing without increasing the printer configuration scale.

In the first means, the printing speed control means may be configured to reduce the printing speed according to the unprinted data amount when the unprinted data amount is less than a predetermined value. The control of the printing speed may be performed based on the amount of unprinted data in the image buffer memory that temporarily stores the image data for printing. If a means for limiting the amount of change in the printing speed control value is provided, it is possible to prevent uneven printing due to a sudden change in the printing speed.

According to the second means of the present invention, in the printer of the above-mentioned sequential printing system, the buffer memory for temporarily storing the data transferred from the host to the printing and the print data in the print stop prohibited section are provided. When printing is performed, the control means for delaying the start of printing in the section by the set time is provided to prevent the printing from being stopped in the printing stop prohibited section. As a result, it is possible to prevent the print unevenness in the print stop prohibition section with the minimum required buffer memory capacity.

In the second means, the print stop prohibition section can be determined based on the print stop prohibition code distributed from the host. The second means can be realized by, for example, the configuration specified by the following (1) to (3). (1) A part of the system memory used in the printer control system is allocated to a buffer memory for temporarily storing transfer data. (2) The minimum required print start delay time is set so that the transfer data amount transition in the print stop prohibited section always exceeds the print data amount transition. (3) The buffer memory capacity necessary for temporarily storing the data transferred during the print start delay time is allocated from the system memory.

In the second means, if the printing speed is set constant, the printer structure can be further simplified.

[0011]

1 is a functional block diagram showing a first embodiment of a printer according to the present invention. The main part of the printer shown in the figure is a communication I / F (interface) 10,
Reception buffer memory 12, image conversion unit 14, image buffer memory 16, printing unit 18, data amount measuring unit 2
0, and the print speed control unit 22 and the like.

In FIG. 1, a communication I / F 10 receives print data distributed from a host via a public communication network and / or a communication line such as a LAN. The received print data is temporarily stored in the reception buffer memory 12. The print data at this time is not image data for printing, but is code (encoding) data in which information for generating the image data is described according to a predetermined format.

The print data accumulated in the reception buffer memory 12 are sequentially read out and transferred to the image conversion unit 14. The image conversion unit 14 performs code analysis on the print data to generate print image data. The generated image data is once held in the image buffer memory 16 and then printed by the printing unit 18 line by line.
The printing unit 18 feeds the recording paper in the main scanning direction (the direction orthogonal to the line) while pitching the image buffer memory 1.
The image data given via 6 is printed in the sub-scanning direction (line direction). Printing is performed one line or a plurality of lines at a time.

The data amount measuring unit 20 measures the amount of print data remaining in the reception buffer memory 12 in the print waiting state, that is, the print waiting data remaining amount (unprinted data amount). The print speed control unit 22 variably controls the print speed (pitch speed) in the print unit 18 according to the remaining amount of print waiting data. Both the data amount measuring unit 20 and the printing speed control unit 22 can be configured by software using a microcomputer that is the core of the printer control system.

FIG. 2 is a graph showing an example of a control program of the print speed with respect to the remaining amount of the print waiting data. As shown in the figure, the printer described above incorporates a speed control program for setting the printing speed to be slower according to the decrease of the remaining amount of the print waiting data when the remaining amount of the print waiting data becomes small. This control program can be constructed using, for example, table data stored in an appropriate non-volatile memory in which the print data amount and the print speed control value are associated with each other.

In FIG. 2, the printer executes printing at a predetermined steady speed when the remaining amount of data waiting to be printed is above a certain level, but when the remaining amount of data waiting to be printed decreases below a certain level, the printing speed is correspondingly reduced. Slow down. As a result, it is possible to avoid the printing stop due to the interruption of the print data without using the page memory. If the printing is not stopped, that is, if the printing operation is continued even at a low speed, the printing unevenness due to the disturbance of the printing pitch does not occur.

In the above-mentioned embodiment, the control of the printing speed is carried out based on the print waiting data remaining amount of the receiving buffer memory 12, but the print waiting data remaining amount (unprinted data amount) of the image buffer memory 16 is provided. You may make it based on. In the image buffer memory 16,
The image data for printing generated from the received data (code data) is held, but if the printing speed is controlled based on the remaining print waiting amount of this image data, the image data generation process can be performed by, for example, complicated character decoration. Even if there is a delay in printing, it is possible to avoid printing stop due to the processing delay of the image data. As a result, it is possible to more reliably prevent uneven printing due to a temporary stop of printing.

FIG. 3 is a functional block diagram showing a second embodiment of the present invention. Explaining the difference from the above-described first embodiment, the second embodiment is characterized in that a limiter unit 24 is provided to apply a certain limit to the amount of change in the printing speed due to the change in the remaining amount of print waiting data. . The printing unevenness is caused by a temporary stop of printing, but may occur to some extent even when the printing speed suddenly changes. By providing the limiter unit 24, it is possible to prevent the printing speed control value from changing suddenly even if the remaining amount of print waiting data changes suddenly, and thus it is possible to prevent printing unevenness more reliably. Like the data amount measuring unit 20 and the printing speed control unit 22, the limiter unit 24 can be configured by software.

FIG. 4 shows an example of a state in which the remaining amount of print waiting data changes with time (solid line curve) and a state in which the printing speed changes with time (broken line) in the configuration of the second embodiment.

FIG. 5 is a functional block diagram showing a third embodiment of the present invention. The third embodiment is particularly applied to a printer such as a POS terminal, which is equipped in a device in which the environment for communication with the host and the host does not change so much and which often prints a fixed format. It is valid.

The printer of the third embodiment has a communication I / F.
10, a reception buffer memory 12, an image conversion unit 14,
In the sequential printing type printer having the image buffer memory 16, the printing unit 18, etc., the print stop prohibited section determination unit 3
0, a data transfer rate measuring unit 32, a transfer interruption period measuring unit 34, a print timing setting unit 36, and a buffer capacity setting unit 38.

The print stop inhibition section determination unit 30 determines a section which should be continuously executed without stopping printing, that is, a print stop inhibition section. This determination is made based on the print stop prohibition code embedded in the print data delivered from the host. The print stop prohibition code indicates the prohibition of the print stop and the range of the prohibition (for example, the number of print lines). For example, a print stop prohibition code for prohibiting the print stop while the data part is printed is added to the print data part of a specific range such as a logo where print unevenness due to the print stop is conspicuous.

The data transfer rate measuring unit 32 measures the data transfer rate in the print stop prohibited section. The transfer interruption period measuring unit 34 measures the data transfer interruption period occurring in the print stop prohibition section. These measurement results are used as calculation parameters for calculating the minimum required buffer memory capacity.

When the print stop prohibition code is detected, the print timing setting section 36 performs a pause (temporary stop) control for delaying the print start timing of the print stop prohibition section designated by the prohibition code. The pause period (print start delay time) Td is calculated based on the transfer rate, the transfer interrupt period, and the print speed of the printing unit 18. In this calculation, the transfer data amount (transferred data amount) change is always the print data amount (printed data amount) change during the period (print stop prohibition period) during which the print data in the print stop prohibited area is transferred and printed. The minimum time required to exceed this is the condition.

That is, as shown in the graph of FIG. 6, when the print data in the print stop prohibited section is started, the pause period (Td) for delaying the print start timing of the data in the print stop prohibited section. Put. The print data transferred within this pause period (Td) is accumulated in the buffer memory 12. When the pause period (Td) has elapsed, the printing unit 18 prints the print data accumulated in the buffer memory 12 at a constant speed. The remaining amount of data waiting to be printed in the buffer memory 12 floats while exhibiting a kind of equilibrium state due to a decrease due to printing use and an increase due to new transfer, but the pause period (Td) is set so as not to become zero or less. To do.

In this way, if the pause period (Td) is set so that the transition of the transfer data amount always exceeds the transition of the print data amount, the printing unit 18 interrupts the print data in the print stop prohibition section. It is possible to continue printing at a constant speed. That is, it is possible to print the data in the print stop prohibition section without stopping the print.

For the pause period (Td), the minimum required value can be calculated from the transition of the transfer data amount and the transition of the print data amount. The transfer data amount transition can be obtained by measuring the transfer rate by the data transfer rate measuring unit 32 and measuring the transfer suspending period by the transfer suspending period measuring unit 34. The change in the amount of print data is given by the print speed, but if the print speed is made constant as shown in FIG. 6, the minimum pause period (T
d) can be calculated. The minimum required buffer memory capacity can be calculated from the minimum required pause period (Td) and the printing speed (that is, the amount of print data per unit time). The buffer capacity setting unit 38
A memory area is set to secure the calculated minimum capacity buffer memory 12. In this way, if the capacity of the buffer memory 12 is secured to the required minimum, the data in the print stop prohibited section can be printed without stopping the printing, and the print unevenness can be prevented.

The buffer memory 12 is used by allocating a part of the system memory used by the printer control system (microcomputer) so as not to complicate the configuration of the printer control system. in this case,
By calculating and allocating the minimum required buffer memory capacity as described above, it is possible to reduce the memory load of the printer control system to the maximum and improve its throughput (data processing capacity).

The buffer memory capacity may be calculated and set based on the transition of the transfer data amount measured at the previous data transfer each time the data transfer in the print stop prohibited section is performed. For printers such as terminals that do not change data transfer conditions so much and that are used for printing standard formats, do this only the first time, and keep the initial settings as they are from the next time. Can be used. In other words, the minimum required buffer memory capacity that has been set once will not change unless conditions such as the host or print format change.
You do not have to change it.

The setting or updating of the buffer memory capacity can be automatically performed at the following timings, for example. That is, (a) when the printer initializes the system such as resetting, (b) when a control code instructing initialization is received from the host,
(C) When the user performs a predetermined command input operation,
(D) It can be performed, for example, when an event such as power shutdown occurs.

When a plurality of printers having the same configuration are used under the same condition, the buffer memory capacity setting made by any one printer may be set in a form of copying to another printer. . Further, the buffer memory capacity may be set using a setting data table created under various usage conditions, for example.
In this case, the data transfer rate measuring unit 32 and the transfer interruption period measuring unit 34 can be omitted.

In the third embodiment described above, it is possible to prevent uneven printing by continuously printing without pausing a specific area such as the logo portion. Further, the printing speed during printing may be constant, and it is not necessary to variably control the printing speed. As a result, the structure can be further simplified as compared with the first and second embodiments described above.

In the above-described third embodiment, the pause period (T
Although d) is inserted, the pause period (Td) is the minimum time required to continuously execute the data printing within the print stop prohibition section as described above, and therefore the response of the host upon the start of printing There is no particular problem in confirmation.

[0034]

As is apparent from the description of the embodiments above, the present invention is a printer of a system which does not have a page mode and sequentially prints print data transferred from the host, and is transferred from the host. A buffer memory that temporarily stores data until printing and a print speed control unit that slows the print speed when the amount of unprinted data remaining in the print wait state in this buffer memory decreases As a result, it is possible to effectively prevent print unevenness due to a temporary print stop during page printing without increasing the printer configuration scale.

In addition, when the buffer memory for temporarily storing the data transferred from the host to the printing and the print data in the print stop prohibited section are printed, the print start of the section is delayed by the set time. By providing the control means for preventing the print stop in the print stop prohibition section, it is possible to prevent the print unevenness in the print stop prohibition section with the minimum required buffer memory capacity. You can

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a first embodiment of a printer according to the present invention.

FIG. 2 is a graph showing an example of a print speed control program with respect to the remaining amount of print waiting data.

FIG. 3 is a functional block diagram showing a second embodiment of the printer according to the present invention.

FIG. 4 is a graph showing an example of changes over time in the remaining amount of print waiting data and the print speed.

FIG. 5 is a functional block diagram showing a third embodiment of the printer according to the present invention.

FIG. 6 is a graph showing changes in transfer data amount and changes in print data amount.

[Explanation of symbols]

10 Communication I / F 12 Receive buffer memory 14 Image converter 16 image buffer memory 18 Printing section 20 Data amount measuring unit 22 Print speed controller 24 Limiter section 30 Print stop prohibited area determination unit 32 Data transfer rate measurement unit 34 Transfer interruption period measurement unit 36 Print timing setting section 38 Buffer capacity setting section Td Print start delay time

Claims (8)

[Claims] 1. In a printer of a type that sequentially prints print data transferred from a host, a buffer memory for temporarily storing data transferred from the host and printed, and a print standby state in this buffer memory. 2. A printer comprising a printing speed control means for slowing the printing speed when the amount of unprinted data remaining in 1. becomes small. 2. The printer according to claim 1, further comprising a print speed control unit that reduces the print speed according to the amount of unprinted data when the amount of unprinted data is less than a predetermined value. 3. The printer according to claim 1, wherein the printing speed is controlled based on the amount of unprinted data in the image buffer memory that temporarily stores the image data for printing. 4. The method according to any one of claims 1 to 3,
A printer comprising means for limiting the amount of change in the print speed control value. 5. In a printer of a type that sequentially prints print data transferred from a host on a line-by-line basis, a buffer memory that temporarily stores data transferred from the host until it is printed, and a print stop prohibited section. When the print data is printed, the printer is provided with a control means for delaying the start of printing in the section by a set time, thereby avoiding the print stop in the print stop prohibited section. . 6. The printer according to claim 5, wherein the print stop prohibition section is determined based on a print stop prohibition code distributed from the host. 7. The method according to claim 5 or 6, wherein
A printer specified by (3). (1) A part of the system memory used in the printer control system is allocated to a buffer memory for temporarily storing transfer data. (2) The minimum required print start delay time is set so that the transfer data amount transition in the print stop prohibited section always exceeds the print data amount transition. (3) The buffer memory capacity necessary for temporarily storing the data transferred during the print start delay time is allocated from the system memory. 8. The method according to any one of claims 5 to 7,
A printer characterized by setting a constant print speed.