From around 1934 and into the 1950s, Parker pens (and pencils, though less consistently) were marked on the barrel to indicate their date of production, with nibs marked similarly. At first the code consisted of two digits: the first indicated the
quarter; the second, the year. In the later '30s the code was changed to a single-digit form, with the year number surrounded by up to three dots. Three dots indicated the first quarter; in each subsequent quarter, a dot would be ground off the die, so by the last quarter no dots remained. From 1950, the date was denoted by another two-digit system: "50" was the mark for 1950, and "51" for 1951. The system was dropped not long thereafter (the earliest US date code we have seen is "34"; the latest, "55"). Canadian-made single-jewel Vacumatics were produced into the 1950s, bearing a single-digit date code in a much larger font than that used for US production. A similar date code may also be found on other Canadian-made Parkers of the same era.
从1934年左右到1950年代，派克开始在钢笔笔身和笔舌上进行生产日期标记（也包括铅笔，尽管没有做到始终如一）。起初的代码由两位数字组成：第一位代表生产的季度，第二位代表生产的年份。在30年代晚期，代码变为一位数字格式，由年份数字和环绕的最多3个点构成。3个点表示第一季度，之后每过一个季度减少一个点，所以第四季度表示为没有点。从1950年代开始，用另一种两位代码表示日期：“50”表示1950，“51”表示1951。这种（数字）代码没有使用多长时间（目前可以找到的数字型日期代码美国产为“34”；最晚为“55”）。加拿大制造的单宝石（single-jewel）真空系列一直生产到1950年代，使用比美国产字体大很多的一位数字日期代码。类似的日期代码也可以在同时期加拿大产派克笔上找到。
One will run across anomalies, where pens bear date codes that seem much too late. These seem to be the result of Parker
clearing out stocks of old parts, assembling them into pens years after they were originally produced.
也有不寻常的特例，比如有些笔的生产日期看起来太晚了，似乎是派克清理库存老旧部件的结果——把它们组装成笔的年代远远晚于最初生产的时间。
Parker once again applied date codes to its products starting in the later 1970s. This code uses one of the ten letters in
"QUALITYPEN" to stand for the respective year digit between 0 through 9, followed by another letter in the sequence "E, C, L, I" to designate the quarter. "QC" would thus stand for the second quarter of 1980. Another method of designating the quarter was used from 1987 on, in which the year letter was preceded by three vertical bars in the first quarter, two in the second, one in the third, and none in the fourth.
派克再次在其产品上应用日期代码是在1970年代晚期。这种（两位字符）代码从0至9年依次使用“QUALITYPEN”10个字母，后面一个字母依次使用“E, C, L, I”指明季度。例如“QC”是指1980年第二季度。1987年开始使用另一种表示季度的方法，在年份代码之前用竖条表示季度，3个代表第一季度，2个代表第二季度，1个代表第三季度，第四季度没有。
NOTE: Many 51s from 1946-47 bear a "T" prefix (the examples we have seen run from the 2nd quarter of 1946 to the 2nd quarter of 1947). The commonly-repeated explanation is that the "T" indicates production at Parker's Canadian factory, in Toronto. This is certainly mistaken, however, since these pens are prominently marked "MADE IN U.S.A."
备注：很多1946-47年生产的51系列带有一个字母“T”的前缀（这些例子发生在1946年第二季度至1947年第二季度的产品上）。很多见的一种解释是说“T”表示是由派克位于多伦多的加拿大工厂生产的。这显然是个错误，因为这些笔身上明显的标记着“美国制造”
So what does the "T" signify? Parker's Toronto factory was set up to get around the high tariff barriers between the United
States and the British Empire and Commonwealth. Most Parkers marked "MADE IN CANADA" were destined for export, not for the Canadian market. "T"-marked 51s are found in the USA -- not in Canada or British territories. At the time the "T" code was in use, the postwar surge in demand for 51s was outstripping Parker's production capacity. That demand was strongest in the USA, where there had been wartime shortages but also full wartime employment at high rates of pay. The British postwar economy was much weaker.
那么“T”到底表示的是什么呢？派克的多伦多工厂是为了绕过美国和英联邦之间的高关税壁垒而兴建的。大多数标有“加拿大制造”的派克笔是用于出口的，没有供应加拿大市场。带有“T”标记的51系列都是在美国而不是加拿大或者英国发现的。“T”标记使用的时期，战后经济的急速恢复使得51系列的需求超过了派克的生产能力。这种需求在美国表现的尤为强烈，既有战时短缺的因素也有整个战争时期高工资的原因。而英国的战后经济回复要慢得多。
Given this background, it seems most likely that the "T" code denoted the use of parts made in Toronto (either completely or
partially) in US-assembled pens. Import duty from Canada to the USA would have been much lower for parts, and presumably only a limited number of parts would have come from Canada in order for the pens to still qualify as US-made. This would have been an affordable way for Parker to meet immediate demand until it could expand its US factory capacity.
鉴于上述背景，有理由相信“T”标记的笔是表示使用了多伦多生产的零部件（可能是全部也可能是部分），在美国总装成成品。零部件从加拿大进口到美国的关税要（较笔成品）低得多，推测为了取得美国制造的认证，只有相当有限的零部件是来自加拿大。这样的话，派克就能够在扩大美国工厂生产能力之前，快速满足激增的市场需求。
Another, less likely possibility is that the "T" denoted pens assembled in Canada from US-made parts (since these pens do not resemble Canadian-marked 51s) and brought back to the USA for sale. Whether such pens could have been legally stamped "MADE IN U.S.A." is doubtful, however, and the import duties would surely have been significant. Furthermore, it seems probable that the big production capacity bottleneck was not in final assembly, but rather in the production of components -- in which case assembly in Canada would make little sense.
另外一种可信度较低的说法是，“T”标记表示是由美国产的零部件在加拿大组装，再返回美国进行销售的笔（理由是这些笔和被标记为加拿大制造的51系列并不相似）。且不论这些笔上标记的“美国制造”的合法性是否值得怀疑，（较高的）进口税也是（上述说法）的明显（疑点）。此外，很可能派克最大的产能瓶颈并不是在最终装配环节，而是在零部件制造环节——这样的话在加拿大进行总装毫无意义。作者: novawy 时间: 2009-9-2 11:00
最近进了一支派克75银格子，恕兄弟眼拙，实在是没有找到日期标记，请高人指点，拜谢！作者: novawy 时间: 2009-9-2 12:33
关于“T”标记的51，只找到这么一张不太清楚的照片
