JPH01255569A - Printing apparatus - Google Patents

Abstract

PURPOSE:To enable the correction of density by an ambient temperature or the like without impairing the number of gradation expressions, by providing a measuring means to measure a temperature or the like and a switching control means to switch a selecting means within a prescribed period when data are stored by a storage means, and by controlling a heating time of a heating means. CONSTITUTION:Measured values from a circuit 6 measuring a temperature and a film resistance value are binary-coded by an analog-digital converter 7, and a density correction value corresponding to the measured value is turned into a control signal 9 of l-bits by CPU 8 and preset in a counter 10. Next, a q-bit recording signal stored in a line memory 21 is read out by an address counter 20 and compared with a comparison value in a data processing element 19, and serial data 16 which turn to be 1 when the former is larger than the latter in the above comparison and to be 0 when the former is smaller than the latter therein, are generated. The serial data are synchronous with a shift clock 15, and they are transferred to a shift register 5 and latched at a latch clock 17 generated by a latch timing generating circuit 18 The data which are held are outputted from a selector 3 according to a position selected by a selector control circuit 13, so as to drive a driving element 2 in conformity with 0, 1 of the serial data and thereby to heat a heating element 1.3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing device using a thermal transfer recording method.

[Conventional technology]

Conventionally, in printing devices using a thermal transfer recording method, the print density changes depending on the environmental temperature and the temperature near the heat generating means caused by the heat generated by the heat generating means. Print density has been corrected by making the voltage variable.

In addition, in a printing device that divides the heat generation time of the heat generating means into a stages (a is the number of N) and changes the heat generation amount to express allll, it is possible to obtain the maximum density depending on the environmental temperature, the temperature of the heat generating means, etc. The time that requires a long heat generation time is a>:,
is defined as time (t is time), and when correction is to be made, the density has been corrected by decreasing a.

[Problem to be solved by the invention]

However, in the conventional technology, it is an expensive system to vary the applied voltage, and if the density correction is performed by reducing the number of gradation expressions, the image quality deteriorates.

The present invention is intended to solve the above-mentioned problems, and its purpose is to perform density correction based on environmental temperature, etc., in an inexpensive manner without impairing the number of gradation expressions.

. [Means for Solving the Problems] The printing apparatus of the present invention includes a means for generating heat, a number of driving means equal to the number of the means for generating heat, and a selection means for determining whether or not to drive the driving means. a processing unit that converts the recording means into data for printing; a storage unit that stores the data output from the processing unit for a certain period of time; It is characterized in that it comprises an opening/closing control means that opens and closes, and controls the heat generation time of the heat generating means.

Further, it is characterized in that it includes a measuring means for measuring temperature and the like, and determines the opening/closing period of the opening/closing control means from the measured value outputted from the measuring means.

〔Example〕

Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a block diagram of a printing apparatus according to the present invention.

1 is rn x n (m, n is a natural number) heating means, 2
is m x n driving elements, 3 is 1 heating means, mxk, mXk+1, mXk+2, -' ff in order from the end.
1xk+rn-t (k is a positive integer, mXk+m-1≦m
Xn), and selects one of the divided groups or selects not to drive all drive elements in 2, 4 is a latch, 5 is a shift register, 6 is a temperature and film resistance value 7 is an analog-to-digital converter, 8 is a CPU, 9 is a 1-bit (J is a natural number) control signal, 1o is a 1-bit counter that is preset by the control signal of 9 and counts 23 oscillators, 11 9 is a carry of the counter, 12 is an RS latch, 13 is a decoder, 14 is a signal for selecting one of the divided groups of 3 selection gates or not driving all drive elements 2, 15 is the clock of the shift register 5, 16 is the serial data, 17 is the latch clock, 18 is the latch timing generation circuit, 19 is the data processing section, 20 is the address counter, 21 is the line memory, 22 is the oscillator, 23
is a frequency divider, and 24 is a recording signal of q bits (q is a natural number).

The measured values output from the circuit for measuring temperature and film resistance in 6 are binarized by the analog-to-digital converter in 7, and the CPU in 8 converts the density correction value according to the measured values into the 1-bit data in 9. A control signal is used as a preset value for a counter of 10.

For the purpose of explanation, the q-bit recording signal stored in the 0th order 21 line memory, where m = 5 and j = 8, is read out by the 20 address counters. data are read out sequentially, and one data group out of the five data read out first is assumed to be 5-1 group data. This 5-1 group data is taken into the 19 data processing section, and is compared with the comparison value within the 19 data processing section.
If it is larger than the comparison value, it is set to 1, and if it is smaller, it is set to 0.1
Generates 6 serial data. At this time, the comparison value is CP
0 if initialized by U, n/m
It counts up after each piece of data has been captured. The aforementioned serial data is synchronized with the shift clock No. 15 at the timing shown in the time chart of FIG. 2, and is transferred to the shift register No. 5. After n15 serial data and shift clocks have been transferred, the serial data is latched by 17 latch clocks generated by 18 latch timing generating circuits at the timing shown in the time chart of FIG.

The data held by these 17 latches is placed at the position selected by the 13 selector control circuit (in this case, the position is determined so that the read data of group 5-1 is at a predetermined position). Output from selector 3,
Drive element 2 according to serial data 0.1 (do not drive if serial data is 0), cause heat generating element 1 to generate heat 0 or more From reading out the recording signal described above,
If the period held in the latch circuit of 4 is one gradation and the recording signal is q bits, by repeating this operation two times, one pixel can have a density of 2 levels. (The comparison value mentioned above is counted up by 1 for each gradation.) Also,
Printing of one line is completed by sequentially performing this operation for four groups of data other than the aforementioned 5-1 group data.

Now, in parallel with the above-described one-gradation operation, ten counters preset in eight CPUs count clocks output by twenty-two oscillators. When the counter 10 becomes full, it issues a carry and resets the RS latch 12.

These 12 RS latches are set at the start of the 1st gradation operation, and when set, drive elements are selected from among the 3-pin 1- position selection signals output from the 13 selector control circuits. Possible selection positions (for example, if driving every 5 driving elements, 0 to 4) are reset, and if reset, the selection position where no driving elements are driven (that is, the gate I- of all driving elements is turned OFF) Outputs a signal to select (.). In other words, during the period from the start of the 1st gradation operation until the value of the counter 10 becomes full (this is referred to as tl), a driveable selection position is selected, and after the value of the counter becomes full, the next During the period until the gradation starts (this will be referred to as 2), select a selection position that is not driven.This drive period t1 is controlled by the preset signal of 9 1 pin I of the 10 counters, so it is 2 levels. There is a period of (However, if the period of one gradation is t, t≧t1, t
=t1+t2. ) When moving to the next gradation,
12 by a signal with the same timing as the latch clock of 17
The RS latch is set, and the printing process is sequentially performed in parallel with the one-line printing process described above.

Although it has been described here that the three selection gates are divided and selected, this selection gate can also be realized by a gate that only controls opening and closing.

In addition, although the opening/closing time of the selection gate 3 was controlled by the presettable counter 10, if the CPU 8 has a function to output modulation during pulses, it is possible to directly control the selector control circuit 13 by the CPU 8. Of course, this is true.

〔Effect of the invention〕

As described above, the present invention has the effect of correcting density changes due to environmental temperature, etc., without changing the voltage applied to the heat generating means and without changing the number of Rf1 expressions of one pixel.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment according to the invention. FIG. 2 is a time chart 1 of data transfer according to the present invention. 1...Means for generating heat 2...Drive element 3...Selector 4...Latch 5...Shift register 6...Circuit for measuring temperature, film resistance value, etc. 7...Analog-digital conversion Equipment... CPU 9... Control signal 10... Counter 11... Carry signal 12... RS latch 13... Selector control circuit 14... Select signal 15... Shift register clock 16... ... Serial data 17 ... Latch clock 18 ... Latch timing generation circuit 19 ... Data processing 20 ... Address counter 21 ... Line memory 22 ... Oscillator 23 ... Frequency divider and above Applicant Seiko Epson Co., Ltd. Agent Patent Attorney Picture Book Kisanbe (1 person Ike) TsutsuzR

Claims (2)

[Claims] (1) a means for generating heat; a driving means for driving the means for generating heat; a selection means for opening and closing the driving means; a processing section for converting recording signals into data for printing; a storage means for storing data for a certain period of time; and an opening/closing control means for opening and closing the selection means within a certain period of time during which the storage means stores the data, and controlling the time during which the heat generation means generates heat. A printing device characterized by: (2) The printing apparatus according to claim 1, further comprising a measuring means for measuring temperature or the like, and determining the opening/closing period of the opening/closing control means from the measured value outputted from the measuring means.